Skip to main content

Full text of "Bathymetrical survey of the Scottish fresh-water lochs"

See other formats


UC-NRLF 



1 




SB 



D7b 



iTHYMETRK. 

OF 1 THE 

iSH Y/ATER LOCHS 



SCOTLAND 



i iHE DIRECTION Or 

SIR JOHN MURRAY, K.C.B..HR.S. 

, . .... 

AURENCE PULLAR, HR.S.E. 



C 



Auu 22 Ibl ! 
EXCHANGE 



LIBRARY 

OF THE 

UNIVERSITY OF CALIFORNIA. 

RECEIVED BY EXCHANGE 
Class 



BATHYMETRICAL SUKVEY 

OF THE 

SCOTTISH FRESH-WATER LOCHS 



IRcport on tbe Scientific IResuIts 



PRICE: 

Per set of six volumes, 5, 5s. 
Volume I. separate, 1, Is. 



All the Maps in these volumes are dis- 
sected and mounted on cloth. The 
volumes are half -bound in finest pig-skin. 



BATHYMETRICAL SURVEY 



OF THE 



SCOTTISH FRESH- WATER LOCHS 



CONDUCTED UNDER THE DIRECTION OF 

SIR JOHN MURRAY 

K.C.B., F.R.S., D.Sc., ETC. 

AND 

LAURENCE PULLAE 

F.R.S.E., F.R.G.S. 
DURING THE YEARS 1897 TO 1909 



IReport on tbe Scientific IResnlts 



VOLUME II 



EDINBURGH 
CHALLENGER OFFICE 

1910 



AUt. 22 191 1 
EXCHANGE 



Defcicatefc 

TO THE MEMORY OF 

FREDERICK PATTISON PULLAR 

WHO WAS DROWNED 
WHILE ATTEMPTING TO SAVE THE LIVES OF OTHERS 

ON 15TH FEBRUARY 1Q01 
AT THE AGE OF TWENTY-FIVE YEARS 



He took an active part in the initiation 

of this systematic survey of the 

Scottish Fresh-ivater Lochs 



216510 



PREFACE 

THIS publication consists of six volumes, two of text and 
four of maps, and gives an account of the work done, of 
the observations recorded, and of most of the results 
obtained, during an investigation into the bathymetry of 
the fresh- water lochs or lakes of Scotland between the 
years 1897 and 1909. 

Although the determination of the depths of the lakes, 
and of the general form of the basins in which they lie, 
made up the principal work of the Survey, still a very large 
number of observations were carried out in other branches 
of the science of limnography. Many of these observations 
and the results were published from time to time, as 
the work proceeded, in scientific journals, while others 
now appear in print for the first time. 

Volume I. consists for the most part of new matter. 
It includes numerous articles dealing with the general 
results of the researches from the topographical, geological, 
physical, chemical, and biological points of view, a com- 
parison of Scottish lakes with lakes in other parts of the 
world, and various theoretical considerations. These 
articles have been w r ritten chiefly by gentlemen who have 
taken an active part in the field-work of the Survey. 
This volume also contains an extensive bibliography of 
books and special papers referring to lakes. 

Volume II. contains the special descriptions of the lakes, 
the maps of which appear in Volumes III., IV., V., and VI. 
Throughout the text will be found numerous index-maps, 
showing the drainage areas of the districts in which the 
lochs are situated, together with other illustrations. 

The bathymetrical maps have all appeared during the 
past eight years in the Journal of the Royal Geographical 
Society or in an extra publication of the same Society ; 
and some of the maps have also been published in the 

vii 



viii PREFACE 

Magazine of the Royal Scottish Geographical Society. 
These maps consist of two series. In the first series 
(Volumes III. and IV.), the contours of depth in the lakes 
are shown in shades of blue, and the contours of the height 
of the surrounding land are shown in brown shades of 
colour; in the second series (Volumes V. and VI.), the 
contours of depth are shown in shades of blue, the brown 
shades on the land being omitted. 

In addition to the bathymetrical maps, there are also 
a few maps showing the surface geology, the rainfall, and 
other physical features of some of the districts. 

These maps have all been prepared and printed by 
Dr J. G. Bartholomew, and we desire to express our in- 
debtedness to him for the care with which these have 
been produced, and for his assistance and advice in many 
directions. We are also indebted to Messrs G. Cornwall & 
Sons, Aberdeen, for their assistance and advice with regard 
to the binding of the maps, and to Messrs Neill & Co., Edin- 
burgh, for their advice in connection with the letterpress. 

We feel confident that the whole investigation has 
resulted in very substantial contributions to knowledge. 
Some of the observations those regarding the temperature 
seiche, and the variation of the viscosity of the water with 
temperature, for example throw much light on obscure 
oceanographical problems. Most of the observations 
could, with advantage, have been carried further, by means 
of improved instruments and methods suggested during 
the progress of the work, but it was found necessary to 
terminate the survey, at least in the meantime, and to 
review what had been accomplished. We are conscious 
of many shortcomings. 

In conclusion, we tender our best thanks to all who 
have assisted us in carrying these investigations to a 
successful conclusion. 

JOHN MURRAY. 
LAURENCE PULLAR. 

CHALLENGER OFFICE, EDINBURGH, 
February 1910. 



CONTENTS 

VOLUME I 

PAGE 

Titles ........ i 

Dedication ........ v 

Preface, by Sir JOHN MURRAY and Mr LAURENCE PULLAR . vii 

Contents of each Volume ...... ix 

Statistical Tables of the Scottish Fresh-water Lochs, I. to VI. . xvii 

Index to the Descriptions and Maps of the Scottish Fresh-water 

Lochs sounded by the Lake Survey . . . xlv 

Introduction, Methods, Instruments, and various Appendices, by 

Sir JOHN MURRAY, K.C.B., F.R.S., D.Sc., etc. . . 1 

Seiches and other Oscillations of Lake-surfaces, observed by the 
Scottish Lake Survey, by Professor GEORGE CHRYSTAL, M.A., 
Sec. R.S.E., etc. ...... 29 

Temperature of Scottish Lakes, by E. M. WEDDERBURN, M.A., 

LL.B., W.S., F.R.S.E. ..... 91 

Chemical Composition of Lake-waters, by W. A. CASPARI, B.Sc., 

Ph.D., F.I.C. . . . . . .145 

An Epitome of a Comparative Study of the Dominant Phanero- 
gamic and Higher Cryptogamic Flora of Aquatic Habit, in 
seven Lake Areas in Scotland, by GEORGE WEST . 1 56 

Deposits of the Scottish Fresh-water Lochs, by W. A. CASPARI, 

B.Sc., Ph.D., F.I.C. ...... 261 

Biology of the Scottish Lochs, by JAMES MURRAY, F.R.S.E. 

I. The Biology in relation to Environment . . .275 

II. Census of the Species . . . . .313 

Some Distinctive Characters in the Fresh-water Plankton from 
various Islands off the Xorth and West Coasts of Scotland, 
by JOHN HEWITT, B.A. . . . 335 

ix 



x CONTENTS 

PAGE 

On the Nature and Origin of Fresh-water Organisms, by 

WM. A. CUNNINGTON, M.A., Ph.D. . . . . 354 

Summary of our Knowledge regarding various Limnological Pro- 
blems, by C. WESENBERG-LUND, Ph.D. . . . 374 

The Scottish Lakes in relation to the Geological Features of 
the Country, by B. N. PEACH, LL.D., F.R.S., etc., and 
JOHN HORNE, LL.D., F.R.S., etc. . .439 

Characteristics of Lakes in general, and their Distribution over 
the Surface of the Globe, by Sir JOHN MURRAY, K.C.B., 
F.R.S., D.Sc., etc. . . . . .514 

Bibliography of Limnological Literature, compiled in the 

Challenger Office by JAMES CHUMLEY . . . 659 

Index of Genera and Species . . . .754 

General Index ....... 765 

VOLUME II 

Titles . i 

Dedication ........ v 

Preface, by Sir JOHN MURRAY and Mr LAURENCE PULLAR . . vii 

Contents of each Volume ..... ix 

Statistical Tables of the Scottish Fresh-water Lochs, I. to VI. . xvii 
Index to the Descriptions and Maps of the Scottish Fresh-water 

Lochs sounded by the Lake Survey . . . xlv 

PART I 

Descriptions of Scottish Fresh-water Lochs, the maps of which, showing 
the land-contours in shades of brown and the lake-contours in 
shades of blue, are bound in Volumes III. and IV. : 

PAGE 

Lochs of the Forth Basin ..... 1 

Lochs of the Tay Basin ... .53 

Lochs of the Inver Basin . . . .148 

Lochs of the Roe Basin . . 156 

Lochs of the Kirkaig Basin . . 159 

Lochs of the Polly Basin . .168 

Lochs of the Garvie Basin . . .172 

Lochs of the Morar Basin . .195 

Lochs of the Ewe Basin . . .210 

Lochs of the Shiel Basin . .241 

Lochs of the Ailort Basin ..... 249 
Lochs of the nan Uamh Basin 253 



CONTENTS xi 

PAGE 

Lochs of the Conon Basin . . . .261 

Lochs of the Shin Basin . . 293 

Lochs of the Naver Basin . . . . 309 

Lochs of the Borgie Basin . . . . .316 

Lochs of the Kinloch Basin . .321 

Lochs of the Hope Basin .... 324 

Lochs of the Beauly Basin . . . 334 

Lochs of the Lochy Basin . . 355 

Lochs of the Ness Basin 379 



PART II 

Descriptions of Scottish Fresh-water Lochs, the maps of which, showing 
only the lake-contours in shades of blue, are bound in Volumes V. 
and VI. : 

PAGE 

Lochs of the Brora Basin .... 1 

Lochs of the Helmsdale Basin .... 4 

Lochs of the Wick Basin . ... 14 

Lochs of the Wester Basin . . . . .17 

Lochs of the Heilen Basin . ... 17 

Lochs of the Dunnet Basin . . . . .18 

Lochs of the Thurso Basin ... 19 

Lochs of the Forss Basin . . . . .20 

Lochs of the Laxford Basin . . . . .24 

Lochs of the Scourie Basin . . . . .30 

Lochs of the Badcall Basin . 32 

Lochs of the Duartmore Basin . . . .34 

Lochs of the Broom Basin . . 37 

Lochs of the Gruinard Basin .... 40 

Lochs of the Gairloch Basin . 49 

Lochs of the Torridon Basin . . . . .58 

Lochs of the Carron Basin ... 60 

Lochs of the Alsh Basin . . . . .63 

Lochs of the Aline Basin . . 65 

Lochs of the Leven Basin . . 68 

Lochs of the Oban Basin . . . . .73 

Lochs of the Feochan Basin . . . . .74 

Lochs of the Seil Basin . 77 

Lochs of the Melfort Basin .... 78 

Lochs of the Eachaig Basin . . 87 

Lochs of the Doon Basin . . 91 

Lochs of the Girvan Basin . . . . .96 

Lochs of the Stinchar Basin . ... 98 

Lochs of the Ryan Basin . . 99 



xii CONTENTS 

PAGE 

Lochs of the Galdenoch Basin . . . .101 

Lochs of the Luce Basin . .103 

Lochs of the Bladenoch Basin . . . .106 

Lochs of the Cree Basin ... 109 

Lochs of the Fleet Basin . . . .113 

Lochs of the Dee (Kirkcudbright) Basin . . . 114 

Lochs of the Urr Basin . . . .123 

Lochs of the Nith Basin . 126 

Lochs of the Annan Basin . . . .129 

Lochs of the Tweed Basin . . . .134 

Lochs of the Monikie Basin . . . . .141 

Lochs of the Lunan Basin . . . . .143 

Lochs of the Dee (Aberdeen) Basin . . . .145 

Lochs of the Spey Basin . . . . .152 

Lochs of the Lossie Basin . . . .162 

Lochs of the Findhorn Basin . . . . 1 64 

Lochs of the Nairn Basin . . . . .167 

Reservoirs of the Forth Basin . . . . .250 

Lochs of the Clyde Basin . ... 262 

Lochs of the Etive Basin . . . . .270 

Lochs of Bute ....... 84 

Lochs of Lismore . . . . .171 

Lochs of Mull .... 173 

Lochs of Benbecula . . . . . .177 

Lochs of North Uist . . . . . .183 

Lochs of Lewis . . . . . .205 

Lochs of Orkney .... . 222 

Lochs of Shetland 231 



VOLUME III 

Titles .... i 

Dedication ....... v 

Preface, by Sir JOHN MURRAY and Mr LAURENCE PULLAR . . vii 

Contents of each Volume ...... ix 

Statistical Tables of the Scottish Fresh-water Lochs, I. to VI. . xvii 
Index to the Descriptions and Maps of the Scottish Fresh-water 

Lochs sounded by the Lake Survey . . . xlv 

Maps of the Lochs in the Basins of the Forth, Tay, Inver, Roe, Kirkaig, 

Polly, Garvie, Morar, and Ewe : 

Lochs of the Forth Basin . . Plates I. to XI. 

Lochs of the Tay Basin . . Plates XII. to XXXIV. 



CONTENTS xiii 

Lochs of the Inver Basin . Plates XXXV. and XXXVI. 

Lochs of the Roe Basin . Plate XXXVII. 

Lochs of the Kirkaig Basin . Plate XXXVIII. 

Lochs of the Polly Basin . Plate XXXIX. 

Lochs of the Garvie Basin . Plates XL. to XLII. 

Lochs of the Morar Basin . Plates XLIII. to XLV. 

Lochs of the Ewe Basin Plates XLVI. to LI. 



VOLUME IV 

PAGE 

Titles ........ i 

Dedication ........ v 

Preface, by Sir JOHN MURRAY and Mr LAURENCE PULLAR . . vii 

Contents of each Volume ...... ix 

Statistical Tables of the Scottish Fresh- water Lochs, I. to VI. . xvii 
Index to the Descriptions and Maps of the Scottish Fresh-water 

Lochs sounded by the Lake Survey . . . xlv 

Maps of the Lochs in the Basins of the Shiel, Ailort, nan Uamh, Conon, 
Shin, Naver, Borgie, Kinloch, Hope, Beauly, Lochy, and Ness : 

Lochs of the Shiel Basin . Plates LII. to LIV. 

Lochs of the Ailort Basin . Plate LV. 

Lochs of the nan L'amh Basin . Plate LVI. 

Lochs of the Conon Basin . Plates LVII. to LXIV. 

Lochs of the Shin Basin Plates LXV. to LXX. 

Lochs of the Xaver Basin Plates LXXI. to LXXIII. 

Lochs of the Borgie Basin Plates LXX IV. and LXXV. 

Lochs of the Kinloch Basin . Plate LXXVI. 

Lochs of the Hope Basin . Plate LXXVII. 

Lochs of the Beauly Basin . Plates LXXVIII. to LXXXII. 

Lochs of the Lochy Basin . Plates LXXXIII. to XC. 

Lochs of the Ness Basin Plates XCI. to CV. 



VOLUME V 

PAGE 

Titles .......... i 

Dedication ........ v 

Preface, by Sir JOHN MURRAY and Mr LAURENCE PULLAR . vii 

Contents of each Volume ...... ix 

Statistical Tables of the Scottish Fresh- water Lochs, I. to VI. . xvii 
Index to the Descriptions and Maps of the Scottish Fresh-water 

Lochs sounded by the Lake Survey . xlv 



XIV 



CONTENTS 



Maps of the Lochs in the Basins of the Brora, Helmsdale, Wick, 
Wester, Heilen, Dunnet, Thurso, Forss, Laxford, Scourie, Badcall, 
Duartmore, Broom, Gruinard, Gairloch, Torridon, Carron, Alsh, 
Aline, Leven, Oban, Feochan, Seil, Melfort, Eachaig, Doon, 
Girvan, Stinchar, Ryan, Galdenoch, Luce, Bladenoch, Cree, Fleet, 
Dee (Kirkcudbright), Urr, Nith, Annan, Tweed, Monikie, Lunan, 
Dee (Aberdeen), Spey, Slains, Lossie, Findhorn, and Nairn ; and 
in the Islands of Bute, Lismore, and Mull : 



Lochs of the Brora Basin 

Lochs of the Helmsdale Basin 

Lochs of the Wick Basin 

Lochs of the W r ester Basin 

Lochs of the Heilen and Dunnet 

Basins .... 
Lochs of the Thurso Basin 
Lochs of the Forss Basin 
Lochs of the Laxford Basin . 
Lochs of the Scourie Basin . 
Lochs of the Badcall Basin . 
Lochs of the Duartmore Basin 
Lochs of the Broom Basin 
Lochs of the Gruinard Basin . 
Lochs of the Gairloch Basin . 
Lochs of the Torridon Basin . 
Lochs of the Carron Basin 
Lochs of the Alsh Basin 
Lochs of the Aline Basin 
Lochs of the Leven Basin 
Lochs of the Oban and Feochan 

Basins .... 
Lochs of the Seil and Melfort Basins 
Lochs in the Island of Bute . 
Lochs of the Eachaig Basin . 
Lochs of the Doon Basin 
Lochs of the Girvan and Stinchar 

Basins .... 
Lochs of the Ryan Basin 
Lochs of the Galdenoch and Luce 

Basins .... 
Lochs of the Bladenoch Basin 
Lochs of the Cree Basin 
Lochs of the Urr Basin 
Lochs of the Dee (Kirkcudbright) 

Basin 



Plate I. 
Plate II. 
Plate III. 
Plate IV. 

Plate V. 

Plate VI. 

Plate VII. 

Plates VIJI. to X. 

Plate XI. 

Plate XII. 

Plate XIII. 

Plates XIV. and XV. 

Plates XVI. and XVII. 

Plates XVIII. and XIX. 

Plate XX. 

Plates XXI. and XXII. 

Plates XXIII. and XXIV. 

Plate XXV. 

Plates XXVI. and XXVII. 

Plates XXVIII. and XXIX. 

Plates XXX. and XXXI. 

Plate XXXII. 

Plate XXXIII. 

Plates XXXIV. to XXXVL 

Plate XXXVII. 
Plate XXXVIII. 

Plate XXXIX. 
Plates XL. and XLI. 
Plate XLII. 
Plate XLIII. 

Plates XLIV. and XLV. 



CONTENTS 



XV 



Lochs of the Fleet and Nith Basins . 
Lochs of the Annan Basin 
Lochs of the Tweed Basin 
Lochs of the Monikie Basin . 
Lochs of the Lunan Basin 
Lochs of the Dee (Aberdeen) Basin . 
Lochs of the Slains and Lossie Basins 
Lochs of the Spey Basin 
Lochs of the Findhorn Basin . 
Lochs of the Nairn Basin 
Lochs in the Island of Lismore 
Lochs in the Island of Mull . 



Plate XLVI. 

Plate XLVII. 

Plates XLVIII. and XL1X. 

Plate L. 

Plate LI. 

Plates LII. to LIV. 

Plate LV. 

Plates LVI. to LXI. 

Plates LXII. and LXIII. 

Plate LXIV. 

Plate LXV. 

Plates LXVI. and LXVII. 



VOLUME VI 



PAGE 

i 



Titles ........ 

Dedication ........ v 

Preface, by Sir JT>HN MURRAY and Mr LAURENCE PULLAR . . vii 

Contents of each Volume ...... ix 

Statistical Tables of the Scottish Fresh-water Lochs, I. to VI. . xvii 
Index to the Descriptions and Maps of the Scottish Fresh- water 

Lochs sounded by the Lake Survey . . . xlv 

Maps of the Lochs in the Islands of Benbecula, North Uist, Lewis, 
Orkney, and Shetland ; and in the Basins of the Etive and Clyde ; 
and of the Reservoirs in the Forth Basin : 



Lochs in the Island of Benbecula 
Lochs in the Island of North Uist 
Lochs in the Island of Lewis . 

Lochs in the Orkney Islands . 
Lochs in the Shetland Islands . 
Reservoirs of the Forth Basin . 
Lochs of the Etive Basin 

Lochs of the Clyde Basin 



Plates LXVIII. and LXIX. 
Plates LXX. to LXXVII. 
Plates LXXVIII. to 

LXXXIX. 

Plates XC. to XCIV. 
Plates XCV. to CVI. 
Plates CVII. to CXVIII. 
Plates CXXIL, CXXIIL, 

CXXVI. to CXXXI. 
Plates CXXIV., CXXV., 

CXXXII. to CXXXIV. 



In addition to the maps showing the depths of the 
lochs, the following maps are included in Vol. III. : 

Plate I. Head-waters of the Forth Orography and drainage areas. 

Plate II. ., Surface geology. 

Plate III. Mean annual rainfall. 

Plate XIV. Temperature Section of Loch Ericht. 

Plate XXXIV. Head- waters of the Tay Surface geology. 

Plate XLI1. Assynt District Surface geology. 

Plate LI. Loch Maree District Surface geology. 



STATISTICAL TABLES OF THE 
SCOTTISH FRESH-WATER LOCHS 

(Surveyed during the years 1897 to 1909) 

DURING the course of the Lake Survey work 562 of the Scottish 
fresh-water lochs were surveyed. These include all the principal 
lochs of the country, and a very large number of the smaller and less 
important ones. As a matter of fact, all lochs were surveyed on 
which boats could be found at the time the work was being carried 
out. To have included all the smaller highland and less accessible 
lochs and tarns would have very greatly increased the expense and 
the time involved. To transport a boat to many of the remote 
lochs in the Highlands would have entailed much labour and 
difficulty, not to speak of the objections of proprietors, keepers, and 
others, who do not wish to have grouse moors and deer forests dis- 
turbed at a time of the year when the lochs are most accessible. 

The general results of the survey work are, however, in no way 
affected by these smaller lochs having been excluded, for a great 
many lochs have been surveyed in all districts of the country. 

The following tables are intended to summarise the results which 
are given in detail in Volume II. of this Report. 

Table I. shows the lakes arranged according to their lengths. 

Table II. shows the lakes arranged according to their superficial 
areas. 

Table III. shows the lakes arranged according to their maximum 
depths. 

Table IV. shows the lakes arranged according to their mean 
depths. 

Table V. shows the lakes arranged according to the volume of 
water in each. 

Table VI. shows : 

(a) The number of lakes surveyed in the various river basins ; 

(b) The number of soundings taken in the lakes of the various 

river basins ; 

xvii b 



xviii THE FRESH- WATER LOCHS OF SCOTLAND 

(/) The volume of water in the lakes of the various river basins 
in millions of cubic feet ; 

(d) The superficial area of the lakes in the various river basins ; 

(e) The extent of the drainage area in the various river basins, 

together with the ratio of the drainage area to the super- 
ficial area of the lakes. 

The information in Table VI. is extracted from the tables given in 
greater detail in the descriptions which will be found in Volume II. 
of this Report. 

From this table it will be seen that 562 lochs have been surveyed, 
and that the number of soundings recorded on the maps of these lochs 
is 59,195. The actual number taken exceeds 60,000. The aggregate 
area of the water-surface is over 340 square miles, and therefore the 
average number of soundings per square mile of surface is 174. 

The aggregate volume of water contained in these 562 lochs is 
estimated at about 1,015,814 millions of cubic feet, or nearly 7 cubic 
miles. The area drained by the lochs is about 6669 square miles, or 
about 19 J times the area of the lochs. 



STATISTICAL TABLES 



xix 



TABLE I 

FRESH-WATCH LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 
ARRANGED ACCORDING TO LENGTH 



Loch. 


Length. 
Miles. 


Loch. 


Length. 
Miles. 


1. Awe (Etive) 


25-47 


55. Beoraid .... 


3-43 


2. Xess .... 


24-23 


56. Dun na Seilcheig 


3-41 


3. Lomond .... 


22-64 


57. Eilt .... 


3-37 


4. Shiel .... 


17-40 


58. na Meide .... 


3-33 


5, Shin .... 


17-22 


59. Avich .... 


330 


6. Tav 


14-55 


60. Stack .... 


3-27 


7. Ericht .... 


14-50 


61. Afiric .... 


3-20 


8. Maree .... 


13-46 


62. Ossian .... 


3-20 


9. Arkaig .... 


1200 


63. Skinaskink 


3-16 


10. Morar .... 


11-68 


64. Cliff .... 


3'16 


11. Lochy .... 


978 


65. Coir' an Fhearna 


3-15 


12. Rannoch .... 


9-70 


66. Ba(Mull) 


3-04 


13. Katrine .... 


8 00 


67. Obisary .... 


3-03 


14. Langavat (Lewis) 


7-86 


68. Merkland 


3-02 


15. Lag^an .... 


7-04 


69. St Mary's 


3-02 


16. Quoich .... 


6-95 


70. nan Cuinne 


3-00 


17. Fannich .... 


6-92 


71. Watten .... 


3-00 


18. Earn . 


6'46 


72. Trealaval .... 


2-90 


19. Assynt .... 


6-36 


73. Cam .... 


276 


20. Naver .... 


6'18 


74. Loyne (East) . 


2-75 


21. Hope .... 


6-13 


75. Tummel . 


2-75 


22. Eck 


6-02 


76. Suainaval .... 


2-68 


23. Fionn (Gruinard) 


576 


77. a' Bhraoin 


2-66 


24. Boon .... 


5-64 


78. Beinn a' Mheadhoin . 


2-64 


25. Laidon .... 


5-30 


79. nan Eun (N. Uist) . 


2-63 


26. Treig .... 


5-10 


80. Fadagoa .... 


2-60 


27. Luichart .... 


5-05 


81. Garry (Tay) 


2-55 


28. Garrv(Ness) . 


4-90 


82. Strom .... 


2-54 


29 Mhor .... 


4-84 


83. Tulla .... 


2-50 


30. Harrav .... 


4-84 


84. Talla .... 


2-47 


31. Ken 


4-62 


85. Fionn (Kirkaig) 


2-40 


32. Frisa .... 


4-50 


86. nan Geir^ann (Mill) . 


2-39 


33. Scadavay (East) 


4'50 


87. Calder .... 


2-32 


34. Laoghal .... 


4-46 


88. Morie .... 


2'30 


35. Clunie (Xess) . 


4-28 


89. Ard .... 


2-30 


36. Mullardoch 


4-16 


90. Grunavat. 


2-26 


37. More (Laxford) 


4-11 


91. Ruthven .... 


2-26 


38. Monar .... 


4-10 


92. Muick .... 


2-22 


39. Veyatie .... 


4-05 


93. Langavat (Benbecula) 


2-20 


40. Glass .... 


4-03 


94. Lochindorb 


2-18 


41. Expansions of River Dee . 


4-02 


95. Ba(Tay) .... 


2-15 


42. Oich .... 


4-02 


96. Bad a' Ghaill . 


2-13 


43. Vennachar 


4-00 


97. Boardhouse 


2 03 


44. Luhnaig .... 


4-00 


98. Grennoch. 


2-02 


45. Damh (Torridon) 


3-93 


99. Dhughaill (Carron) . 


2'02 


46. Lurgain .... 


3-87 


100. Skebacleit 


2-00 


47. Scadavay (West) 
48. Stenness .... 


3-80 
379 


101. Swannay .... 
102. Elide Mor 


2-00 
1-98 


49. na Sheallag 


374 


103. Migdale .... 


1-92 


50. Fada (Ewe) 


3-74 


104. na Salach Uidhre . 


90 


51. Leven .... 


3-65 


105. Urigill .... 


86 


52. Brora .... 


3-53 


106. Beannachan 


85 


53. Voil .... 


3-50 


107. Arienas .... 


85 


54. a' Chroisg 


3-47 


108. Achall .... 


83 



xx THE FRESH-WATER LOCHS OF SCOTLAND 

TABLE I continued 



Loch. 


..ength. 
Miles. 


Loch. 


Length. 
Miles. 


109. na h-Earba (West) . 


1-80 


169. Shurrery .... 


1-28 


110. Fada (N. Uist) . 


1-80 


170. Harperrig 


1-27 


111. Woodhall. 


179 


171. Buidhe (Fleet) . 


1-27 


112. a' Bhealaich (Gairloch) 


1-78 


172. na h-Earba (East) . 


1-27 


113. Thorn .... 


1 -78 


173. Hunder .... 


1-26 


114. Lyon .... 


1-74 


174. Kirbister .... 


1-26 


115. Freuchie .... 


1-74 


175. Bunacharan 


1-26 


116. nah-Oidhche . 


1-73 


176. ant-Seilich 


1-26 i 


117. Castle Seraple . 


172 


177. Martnaham 


1-26 


118. Eye 


1-72 


178. Achray .... 


1-25 


119. an Daimh (Shin) 


1-71 


179. Rescobie .... 


1-24 


120. Baddanloch 


1-70 


180. Beannach (Inver) 


1-24 


121. Chon (Forth) . 


170 


181. Urrahag .... 


1-24 


122. Nell 


1-68 


182. Loch .... 


I -23 


123. Trool .... 


1-68 


183. Droma .... 


1-23 


124. Heouravay 


1-68 


184. Dubh (Gruinard) 


1-23 


125. Leum a' Chlamhain . 


1-62 


185. Muckle Water . 


1-21 


126. Fiodhaig .... 


1-61 


186. an Gead .... 


1-21 


127. Heilen .... 


1-60 


187. Sloy .... 


1-21 


128. Olavat .... 


1-60 


188. Lowes (Tay) . 


1-20 


129. Fad 


1-60 


189. Castle (Bladenoch) . 


1-20 


130. Menteith .... 


1-60 


190. Inbhir .... 


1-20 


131. Ashie .... 


1-60 


191. Maberry .... 


1-19 


132. a' Bhealaich (Naver) 


1-60 


192. Dee 


1-18 


133. a' Bhaid-Luachraich . 


1-57 


193. a' Bharpa 


1-18 


134. Creagach .... 


1-57 


194. Garbhaig .... 


1-18 


135. Owskeich .... 


1-56 


195. an Duin (Spey) 


I'M 


136. Gladhouse 


1-56 


196. Tralaig .... 


116 


137. an Dithreibh . 


1-55 


197. an Strom ore 


1-15 


138. Scamadale 


1-54 


198. na Leitreach 


1-14 


139. an Ruathair 


1-54 


199. Oban nam Fiadh 


I'M 


140. Garve .... 


1'54 


200. Sgamhain 


1-12 


141. a' Chlair (Helmsdale) 


1-53 


201. Calavie .... 


1-12 


142. Fada (Gruinard) 


1-52 


202. Killin .... 


1-12 


143. Mochrum .... 


1-50 


203. nam Breac 


1-12 


144. a' Ghriama 


1-50 


204. an Eilein (Spey) 


1-10 


145. Threipmuir 


1-50 


205. Milton .... 


1-10 


146. Girlsta .... 


1-48 


206. Meiklie .... 


1-10 


147. Finlas .... 


1-46 


207. Auchenreoch 


1'08 


148. Poulary .... 


1-46 


208. Forfar .... 


1-07 


149. an Tomain 


1-45 


209. Crogavat .... 


1-06 


150. Caravat .... 


1-45 


210. Kinord 


1-06 


151. Lungard .... 


1-44 


211. Benachally 


1.05 


152. Dilate .... 


1-43 


212. a'Bhaillidh . 


1-04 


153. an Duin (N. Uist) . 


1-40 


213. Turret .... 


1-04 


154. Crocach . . 


1-40 


214. More Barvas 


1-04 


155. Gorm Loch Mor 


1-39 


215. Gartmorn .... 


1-04 


156. Glair (Ewe) 


1-38 


216. Insh .... 


T03 


157. Lintrathen 


1-38 


217. Moy .... 


1-03 


158. Black (Ryan) . 


1-36 


218. Borralan .... 


1-03 


159. Strandavat 


1-36 


219. Pattaek .... 


1-03 


160. a' Chuilinn (Conoii) . 


1-35 


220. Morlich .... 


1-02 


161. lubhair .... 


1-35 


221. Tingwall .... 


1-02 


162. Kernsary .... 


1-35 


222. an Staca .... 


1-02 


163. Coulin(Ewe) . 


1-33 


223. ic Colla .... 


i-oo 


164. Kilbirnie .... 


1-32 


224. na Craobhaig . 


i-oo 


165. Spiggie 
166. Hundland 


1-30 
1-30 


225. Vatandip .... 
226. Gainmheich (South) . 


i-oo 
i-oo 


167. Knockie .... 


1'30 


227. Wester .... 


1-00 


168. Loyne(West) . 


1-28 


228. Drunkie .... 


i-oo 



STATISTICAL TABLES 

TABLE I continued 



XXI 



Loch. 


Length. 
Miles. 


Loch. 


Length. 
Miles. 


229. Arklet .... 


i-oo 


289. na Creige Duibhe 


0-80 


230. Doine .... 


I'OO 


290. na Moracha 


0-80 


231. an Lagain 


1-00 


291. Kindar .... 


0-80 


2:32. Skaill .... 


0-98 


292. Builg .... 


0-80 


233. Skene(Dee) 


0-98 


293. Kirk Dam 


0-80 


231. na Beinne Baine 


0-97 


294. Cro Criosdaig . 


0-80 


235. Bodavat .... 


0-96 


295. Eela 


079 


236. Cuil na Sithe . 


0-96 


296. Chaluim .... 


0'78 


237. Daimh (Tay) . 


0-96 


297. Skiach .... 


0*78 


238. Ailsh .... 


0-95 


298. Hempriggs 


077 


239. Cuil Airidh a' Flod . 


0-94 


299. Lochrutton 


077 


240. Alvie .... 


0-94 


300. Airidh na Lie . 


0-76 


241. Gryfe .... 


0-94 


301. Raoinavat 


076 


242. na Cuaich 


0-94 


302. Gelly .... 


076 


243. Con (Tay) 
244. Dungeon .... 


0-94 
0-93 


303. Lundie (Garry) 
304. na Moine Buige 


076 
076 


245. Skealtar .... 


0-93 


305. Araich-Lin 


075 


246. Clousta .... 


0-92 


306. an Laig Aird . 


074 


247. Dubh (Gahioch) 


0-92 


307. Davan .... 


074 


248. Xant .... 


0-90 


308. nam Breac Dearga . 


074 


1 249. Tollie .... 


0-90 


309. Muckle Lunga . 


074 


250. Hermidale 


0-90 


310. nan Deaspoirt . 


074 


251. Huna .... 


0-90 


311. Bran .... 


074 


252. Bradan .... 


90 


312. Howie .... 


074 


253. Fitty . 


0-90 


313. a' Ghobhainn . 


073 


254. Peppermill 


0-90 


314. Druim Suardalain . 


073 


255. North-house 


0-90 


315. na Lairige 


073 


256. Oehiltree .... 


0-89 


316. Stacsavat. 


072 


257. White (Ryan) . 


0-88 


317. an Drainc 


072 


258. Ceo-Glas 


0-88 


318. Skeen (Annan) 


072 


259. Allt an Fhearna 


0-88 


319. Sguod .... 


072 


260. Eigheach .... 


0-88 


320. Broom .... 


072 


261. Achilty .... 


0-87 


321. Skerrow .... 


070 


262. Tankerness 


0-86 


322. na Bi 


070 


263. More (Thurso) . 


0-86 


323. Eileach Mhic' illeRiabbaich 


070 


264. a' Bhaid Daraich 


0-86 


324. Tearnait .... 


070 


265. Crombie Den . 


0-86 


325. Syre .... 


070 


266. Lunn da-Bhra . 


0-86 


326. Gaol na Doire . 


070 


267. Drumellie 


0-86 


327. Long .... 


070 


268. a' Mhuillin 


0-84 


328. nan Lann 


070 


269. Vaara .... 


0-84 


329. Carlingwark 


070 


270. Achanalt .... 


0-84 


330. Benisval .... 


070 


271. Callater .... 


0-84 


331. Bad an Sgalaig 


0-69 


Lowes (Tweed) 


0'84 


332. Spynie .... 


0-69 


273. Obau a ; Chlachain . 


0-84 


333. Tartf .... 


0-69 


274. Ussie .... 


0-84 


334. Tormasad. 


0-69 


275. Lindores .... 


0-84 


335. Seil 


0-68 


276. Scarmclate 


0-84 


336. Ghuiragarstidh 


0-68 


Triud air Sgithiche . 


0-84 


337. Baile a' Ghobhainn . 


0-68 


278. a' Bhuird 


0-84 


338. Crunachau 


0-68 


279. na Moine 


0-83 


339. Rosebery .... 


0'68 


280. Castle (Annan) . 


0-83 


340. Drummond 


0-68 


Braigh Horrisdale . 


0-82 


341. Kennard . 


0-68 


282. Ghuilbinn 


0-82 


342. Deoravat .... 


0-68 


283. na h-Achlaise . 


0'82 


343. Clings .... 


0-68 


284. St John's. 


0-82 


344. na h- Airidh Sleibhe . 


0-68 


285. Awe(Inver) . 


0-82 


345. Dornal .... 


0-68 


286. Giorra .... 


0-82 


346. Bogton .... 


0-66 


287. an Tuirc .... 


0-81 


347. Portmore .... 


0-66 


288. Linlithgow 


0-80 


348. an Eilein (Gairloch) . 


0-66 



xxii THE FRESH- WATER LOCHS OF SCOTLAND 

TABLE I continued 



Loch. 


Length . 
Miles. 


Loch. 


Length. 
Miles. 


349. a' Bhealaich (Alsh) . 


0-66 


409. Whinyeon 


0-56 


350. Stormont .... 


0-66 


410. a' Chonnachair 


0-56 


351. Morsgail .... 


0'66 


411. an Nostarie 


0'56 


352. Dibadale .... 


0-66 


412. Whitefield 


0-56 


353. an t-Slagain 


0-65 


413. na Ceithir Eileana . 


0-56 


354. Ordie .... 


0'64 


414. Sron Smeur 


0-56 


355. Gleann a' Bhearraidh 


0-64 


415. Gown (South) . 


0-55 


356. Grass .... 


0-64 


416. Moraig .... 


0'55 


357. Raonasgail 


0'64 


417. Monzievaird 


0-55 


358. Sealbhag .... 


0-64 


418. Coire nam Meann 


0-54 


359. Bosquoy .... 


0-64 


419. Kilconquhar 


0-54 


360. Valtos .... 


0-64 


420. na Stainge 


0-54 


361. Beannach (Gruinard) 


0-63 


421. a' Mhiotailt 


0-54 


362. Arthur .... 


0-63 


422. Bruadale .... 


0-54 


363. Edgelaw .... 


0-62 


423. Asta . . ... 


0-53 


364. Bad a' Chrotha 


0-62 


424. L T anagan .... 


0-52 


365. Roer .... 


0-62 


425. Burga .... 


0-52 


366. Craggie .... 


0-62 


426. Allan .... 


0-52 


367. na Deighe fo Dheas . 


0-62 


427. an Losgainn M6r 


0-52 


368. Allt na h-Airbhe 


0'62 


428. Kemp 


0-52 


369. Doire nam Marc 


0-62 


429. Monk Myre 


0-52 


370. an Laghair 


0-62 


430. nan Druimnean 


0-52 


371. Dochart .... 


0-62 


431. Lochinvar 


0-52 


372. Fiart .... 


0-62 


432. Flugarth .... 


0-52 


373. an Tachdaidh . 


0-62 


433. a' Bnaille 


0-52 


374. Clunie (Tay) . 


0-62 


434. na Coinnich 


0-51 


375. Urr 


0-62 


435. an Leoid .... 


0-50 


376. Dochard .... 


0-62 


436. an t-Seasgain . 


0-50 


377. Scaslavat .... 


0-62 


437. Aithness .... 


0-50 


378. a' Chlachain (Lewis) 


0-62 


438. Balgavies. 


0-50 


379. Black (Etive) (East) . 


0-62 


439. Bnrntisland . 


0-50 


380. nam Faoileag . 
381. Leitir Easaich . 


0-62 
0-61 


440. Havperleas 
441. Eldrig .... 


0-50 
0-50 


382. a' Choire .... 


0-61 


442. Littlester. 


0-50 


383. Harelaw .... 


0-60 


443. Kilcheran 


0-50 


384. an Droighinn . 


0-60 


444. na Doire Daraich 


0-50 


385. Leodsay .... 


0-60 


445. Tarruinn an Eithir . 


0-50 


386. Isbister .... 


0-60 


446. na Sreinge 


0-50 


387. Burraland 


0-60 


447. Mhic' ille Riabhaich 


0-49 


388. Sabiston .... 


0-60 


448. Hosta .... 


0-49 


389. Snarravoe 


0'60 


449. Breaclaich 


0-49 


390. Ederline .... 


0-60 


450. Peerie .... 


0-48 


391. Airidh na Ceardaich 


0-60 


451. a' Chlachain (Nairn) 


0-48 


392. Dhomhnuill Bhig . 


0-60 


452. nan Eun (Ness) 


0'48 


393. an lasgaich 


0-59 


453. Monikie (South) 


0-48 


394. Lochaber .... 


0-59 


454. Punds .... 


0-48 


395. Derculich. 


0-59 


455. na Craige 


0-48 


396. Bhradain .... 


0-58 


456. a' Ghlinne Dorcha . 


0-47 


397. nan Gabhar 


0-58 


457. Moor Dam 


0-47 


398. Phitiulais 


0-58 


458. Lundie (Cluriie) 


0-46 


399. Craiglush. 


0-58 


459. Shechernich 


0-46 


400. Butterstone 


0-58 


460. Liath .... 


0'46 


401. Veiragvat 


0-58 


461. Essan .... 


0-46 


402. Derclach .... 


0'58 


462. Fithie .... 


0-46 


403. Soulseat .... 


0-58 


463. a' Phearsain 


46 


404. Gown (North) . 


0-57 


464. nan Eun (Tay) 


0-45 


405. Black (Etive) (West) 


0-56 


465. a' Vullan 


0-45 


406. Black (Etive) (Mid) . 


0-56 


466. Rae 


0-44 


407. White of Myrton 


0-56 


467. Holl 


0-44 


408. Dhugaill (Torridon) . 


0-56 


468. an Duna .... 


0-44 



STATISTICAL TABLES 

TABLE I continued 



xxm 



Loch. 


Length. 
Miles. 


Loch. 


Length. 
Miles. 


469. Brow .... 


0-44 


517. Brough .... 


0-32 


470. Lochnaw .... 


0-44 


518. Geal 


032 


471. Dallas .... 


0'43 


519. Kilchoan (Upper) . 


0-32 


472. Mill 


0-43 


520. a' Chaoiuinn 


0-32 


473. Dubh(Ailort) . 


0-43 


521. Sior 


0-32 


474. Muck .... 


0-42 


522. na Garbh- Abhuinn Ard . 0'32 


475. Clickhimin 


0-42 


523. Kinghorn. . . . 0'31 


476. Harrow .... 


0-4-2 


524. a'Chladhaich . . . 0'31 


477. Kirk .... 


0-42 


525. nan Losganan . 


0-30 


478. Monikie (North) 


0-42 


526. Hightae Mill . 


0-30 


479. Gamhna .... 


0-42 


527. Dubh-M6r 


0-30 


480. Lochenbreck . 
481. nah-Ealaidh . 


0-42 
0-42 


528. Beag .... 
529. Sand .... 


0-30 
0-29 


482. na Claise Fearna 


0-42 


530. Duartmore 


0-29 


483. nan Geireann . 


0-41 


531. Clubbi Shuns . 


0-29 


484. Lure .... 


0'40 


532. Hostigates 


0-28 


485. Sandy .... 


0'40 


533. Scoly .... 


0-28 


486. nan Garbh Chlachain 


0-40 


534. nan Rath .... 


0-28 


487. Bhac .... 


0-38 


535. Black (Tay) . 


0-28 


488. Broiiiter .... 


0-38 


536. Drumlamtbrd . 


0-28 


489. Fleet .... 


0-38 


537. nan Auscot 


0-27 


490. Hoglinns .... 


0-38 


538. na Creige Leithe 


0-27 


491. Collaster .... 


0-38 


539. Cults .... 


026 


492. na Beiste .... 


0-37 


540. Skae 


0-26 


493. Mama . 


0-37 


541. Cornish '. 


0-26 


494. Fyntalloch 


0-37 


542. Kirriereoch 


0-26 


495. Auchenchapel . 


0-37 


543. Eion Mhic Alabtair . 


0-25 


496. Birka .... 


0-36 


544. na Beithe 


0-25 


497. Aboyne .... 


0-36 


545. an Dubh (Lochy) . 


0-24 


498. na Garbh- Abhuinn . 


0-36 


546. an Tairbeirt Stuadhaich . 


0-23 


499. Hoil .... 


0-36 


547. Magillie .... 


0-22 


500. Blairs .... 


0-36 


548. Tutach .... 


0-22 


501. Gainmheich (North) . 


0-36 


549. Crann .... 


0-22 


502. a' Bhainne . . . 0'36 


550. Setter .... 


0-22 


503. Kilchoan (Lower) 


0-36 


551. Pitlyal .... 


0-21 


504. Tilt 


0-35 


552. na Gealaich 


0-21 


505. Anna .... 


0-35 


553. Choire na Cloich 


0'20 


506. Aslaich .... 


0-35 


554. Dubh (Forth) . 


0-20 


507. Fingask .... 


0-35 


555. Loch on Eilean Subhainn 




508. Dubh (Etive) . 


0-35 


(Maree) 


0-18 


509. Maol a' Choire . 


0-34 


556. Dubh (Ness) . 


0-18 


510. Laide .... 


0-34 


557. na h-Eaglais . 


0-16 


511. White (Tay, . 


0'34 


558. Uaine .... 


0'14 


512. Duddingston . 


0-34 


559. St Margaret's . . 


0-13 


513. Kinellan .... 


0-33 


560. Dhu (Portsonarhan) . 


012 


514. Fender ... 


0-33 


561. Allt na Mult . 


0-12 


515. Ree 


0-32 


562. Rainbow .... 


o-io 


516. Buidhe(Tav) . 


032 







XXIV 



THE FKESH-WATER LOCHS OF SCOTLAND 



TABLE II 

FRESH-WATER LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 
ARRANGED ACCORDING TO SUPERFICIAL AREA 



Loch. 


Area. 
Square 
Miles. 


Loch. 


Area. 
Square 
Miles. 


1. Lomond .... 


27-45 


54. nan Cuinne 


1-15 


2. Ness 


21-78 


55. Coir' an Fhearna 


1-15 


3. Awe (Etive) 


14-85 


56. Tulla .... 


no 


4. Maree .... 


11-03 


57. Clunie (Ness) . 


1-10 


5. Morar .... 


10-30 


58. Ossian .... 


1-03 


6. Tay 


10-19 


59. Bad a 5 Ghaill . 


1-02 


7. Shin 


8-70 


60. Menteith .... 


1-02 


8. Shiel .... 


7-56 


61. Cam .... 


1-01 


9. Rannoch .... 


7-37 


62. a' Chroisg 


1-00 


10. Ericht .... 


7-21 


63. Stack .... 


0-99 


11. Arkaig .... 


6-24 


64. St Mary's. 


0-99 


12. Lochy .... 


5-91 


65. Baddanloch 


0-99 


13. Leven .... 


5-30 


66. Tummel .... 


0-98 


14. Katrine . . . . i 478 


67. Lubnaig .... 


0-96 


15. Earn . . . .8*91 


68. Ard 


0-94 


16. Harray .... 


378 


69. Swannay .... 


0-94 


17. Fanmch .... 


3-60 


70. Suainaval. . . . 0'94 


18. Fionn (Gruinard) : 


3-52 


71. Veyatie . . . . ' 0'93 


19. Langavat (Lewis) 


3-45 


72. Morie . . . . 0'92 


20. Assynt .... 


3-10 


73. Ba(Tay) . . . . 0'92 


21. Laggan .... 


2-97 


74. Boardhouse . . . 0*89 


22. Quoich .... 


2-86 


75. Brora . . . . 0*88 


23. Laoghal .... 


2-55 


76. Voil 0-88 


24. Stenness .... 


2-46 


77. na Meide .... 0'87 


25. Treig .... 


2-41 


78. Muick . . . . 0-85 


26. Hope .... 


2-35 


79. Lochiudorb . . . 0'84 


27. Naver .... 


2-26 


80. an Ruathair . . . 0'82 


28. Skinaskink 


2-09 


81. Affric . . . . 0-82 


29. Boon .... 


2-04 


82. Beinn a' 'Mheadhoin . 079 


30. Dim na Seilcheig 


1-95 


83. Urigill . . . . 078 


31. Glass .... 


1-86 


84. Oich .... 0-76 


32. Laidon .... 


1-80 


85. anDithreibh . . . 74 


33. Luichart .... 


1-76 


86. Fada (N. Uist) . 


0-70 


34. Garry (Ness) . 


1-75 


87. Merkland. . . . 0'69 


35. Eck 


1-70 


88. nan Geireann (Mill) . . 0'68 


36. Frisa .... 


1-69 


89. Expansions of River Dee . 0'67 


37. Mhor .... 


1-69 


90. a' Bhraoin . . . 0'66 


38. Vennachar 


1-61 


91. Arienas . . . .0'66 


39. More (Laxford) 


1-46 


92. Eilt 


0-66 


40. Watten .... 


1-45 


93. Owskeich .... 


0-65 


41. Fada(Ewe) 


1-44 


94. Lintrathen 


0-62 


42. na Sheallag 


1-37 


95. Garry (Tay) 


0-61 


43. Ken 


1-36 


96. Trealaval .... 


0-61 


44. Damh (Torridon) 


1-33 


97. Grunavat .... 


0-60 


45. Calder .... 


1-32 


98. Gladhouse 


0-59 


46. Lurgain .... 


1-26 


99. Garve .... 


0-59 


47. Bca(Mull). 


1-21 


100. Fiodhaig .... 


0-58 


48. Avich .... 


1-21 


101. Caravat .... 


0-58 


49. Scadavay (West) 
50. Mullardoeh 


1-20 
1-18 


102. Ruthven .... 
103. Beoraid .... 


0-57 
0'55 


51. Monar . 


1-17 


104. Leum a' Chlamhain . 


0-55 


52. Obisary .... 


1-17 


105. na h-Oidhche . 


0-54 


53. a' Chlair (Helmsdale) 


1-17 


106. Freuchie .... 


0-54 



STATISTICAL TABLES 

TABLE II continued 



XXV 



Area. 
Loch. Square 
Miles. 


Loch. 


Area. 
Square 
Miles. 


107. Achall . . . . 0-52 


166. Heilen .... 


0-30 


108. nan Eun (N. Uist) . . 0'52 


167. Skebacleit 


0-30 


109. Ashie . . . . 0'52 


168. nah-Achlaise . 


0"29 


110. Thorn . . . . 0-52 


169. Kinord .... 


0-29 


111. Strom . ! 0'52 


170. a' Bhaillidh 


0-29 


112. a' Bhaid-Luachraich . . 0'51 


171. Hunder .... 


0-29 


113. Nell 50 


172. Truid air Sgithiche . 


0-29 


114. Fadagoa . . .1 0'48 


173. Mov .... 


0-29 


115. Talla . . . ; 0'47 


174. Gorm Loch Mor 


0-29 


116. Morlich . . . . i 0'47 


175. More (Thurso) . 


0-28 


117. Scadavay (East) . . 0'46 


176. Fad 


0-28 


11 N Creagach . . . . 0'46 


177. Knockie .... 


0-28 


119. Skene(Dee) . . . 0'46 


178. Drumellie 


0-27 


120. Grennoch . . . 0'45 


179. Pattack .... 


0-27 


121. Insh . . . . 0-44 


180. an Daimh (Shin) 


0-27 


12-2. a' Bhealaich (Gairloch) . 0'44 


181. Maberry .... 


0-27 


123. Dhughaill (Carron) . . 0'44 


182. Benisval .... 


0-27 


124. Chon (Forth) . . . 0'43 


183. Clubbi Shuns . 


0-27 


125. Loyne (East) . . . 0'43 


184. a' Bhealaich (Naver) 


0-27 


126. Hundland . . . 0'43 


185. Turret .... 


0-26 


127. Beannachan . . . 0'42 


186. Calavie .... 


0-26 


1-JS. na h-Earba (West) . - C'41 


187. Woodhall 


0-26 


129. Migdale . . . . 0'41 


188. an Staea .... 


0-26 


130. a' Ghriama * . . . 0'40 


189. Tollie .... 


0-26 


131. CM' . . . .0-40 


190. Benachally 


0-25 


132. Dee 0'40 


191. Crocach .... 


0-25 


133. an t-Seilich . . . 0'39 


192. Achanalt. 


0-25 


134. Kilbirnie . . . . 0'39 


193. Bunacharan 


0-25 


135. Ailsh . . . . 0-38 


194. Rescobie .... 


0-25 


136. EildeMor . . . 0'38 


195. Skaill . . ' . 


0-24 


137. na Salach Uidhre . . 0'38 


196. Clair(Ewe) 


24 


13>. Lyon . . . . 0'37 


197. na Beinne Baine 


0-24 


139. More Bar vas . . . 0'37 


198. Milton .... 


0-24 


140. Castle (Bladenoch) . . ' 0'36 


199. Ochiltree . . ... 


0-24 


141. Shurrery . . . . | 0'36 


200. an Stromore 


0-24 


142. Mochrum . . . 0'36 


201. Loyne (West) . 


0-24 


143. Harperrig . . . 0'35 


202. Fada (Gruinard) 


0-23 


144. Scamadale . . . ' 0'3o 


203. Davan .... 


0-23 


145. Girlsta . . . . 0'35 


204. Ghuilbinn 


0-23 


146. Kirbister .... 0'35 


205. na h-Earba (East) . 


0-23 


147. Lowes (Tay) . . . 0'34 


206. Garbhaig .... 


0-23 


148. Luugard .... 0'34 


207. Gelly .... 


0-23 


149. Hempriggs . . . 0'34 


208. Achilty . 


0-23 


ir.i.i. Spiggie . . . . 0'34 


209. White (Ryan) . 


0-23 


151. Arklet .... 0-33 


210. Black (Ryan) . 


0"23 


152. Fioiin (Kirkaig) . . j 0'33 


211. Tankerness 


0-23 


153. Eye i 0'33 


212. Inbhir .... 


0-23 


154. Allt an Fhearna . . 0'33 


213. Tralaig .... 


0-23 


155. Urrahag .... 0'33 


214. Trool .... 


0-23 


156. Castle Semple . . . 0'32 


215. Alvie .... 


0-22 


157. Aehrav . . . . 0'32 


216. Olavat .... 


0-22 


Dubh (Gruinard) . . I 0*32 


217. Drunkie .... 


0-22 


159. Meiklie . . . . : 0'31 


218. Gartmorn 


0-22 


160. Kernsarv . . . . ' 0'31 


219. Sgamhain 


0-22 


161. Ussir . . . . 0-31 


220. Fitty .... 


0-22 


162. Scarmclate . . . 0'30 


221. Finfas .... 


0-22 


163. Castle (Annan) . . 0'30 


222. Dilate .... 


0-22 


164. St John's. . . . 30 


223. nam Breac 


0-22 


165. Threipmuir . . . 0*30 


224. Xant .... 


0*22 



xxvi THE FRESH-WATER LOCHS OF SCOTLAND 

TABLE II continued 



Loch. 


Area. 
Square 
Miles. 


Loch. 


Area. 
Square 
Miles. 


225. Bad an Sgalaig 


0-22 


284. a' Ghobhainn . 


0-15 


226. Eela .... 


0-22 


285. an Tomain 


0-15 


227. Doine .... 


0-21 


286. Dubh (Gairloch) 


0-15 


228. Kindar .... 


0'21 


287. na Moracha 


0-15 


229. lubhair . 


0-21 


288. an Drainc 


0-15 


230. Huna .... 


0-21 


289. Chaluim .... 


0-15 


231. Gainmheich (South) . 


0-21 


290. Roer .... 


0-15 


232. Tarff .... 


0-21 


291. Lowes (Tweed) . 


015 


233. Clunie (Tay) . 


0-21 


292. Giorra .... 


0'14 


234. Strandavat 


0-21 


293. Pepper mill 


0-14 


235. Vaara .... 


0-21 


'z94. Drummond 


0-14 


236. Buidhe (Fleet) . 


0-21 


295. Oban nam Fiadh 


0'14 


237. Killin .... 


0-20 


296. an Nostarie 


0-14 


238. Lochrutton 


0-20 


297. anTachdaidh . 


0-14 


239. an Eilein (Spey) 


0-20 


298. an Eilein (Gairloch) . 


014 


240. Skealtar .... 


0-20 


299. Braigh Horrisdale . 


0'14 


241. na Craobhaig . 


0-20 


300. na Moine .... 


0-14 


242. Muckle Water . 


019 


301. Poulary .... 


0-14 


243. Coire nam Meann 


019 


302. Dungeon .... 


0-14 


244. Langavat ( Benbecula) 


0'19 


303. Clings .... 


0-14 


245. an Duin (N. Uist) . 


0-19 


304. Bodavat .... 


0-14 


246. Skerrow .... 


0-19 


305. Stacsavat .... 


0'14 


247. a' Bharpa 


0'19 


306. Broom .... 


0-13 


248. Araich-Lin 


0'18 


307. Bradan .... 


0-13 


249. na Cuaich 


0-18 


308. Isbister .... 


0-13 


250. Ordie .... 


0-18 


309. Loch .... 


0-13 


251. Gryfe .... 


0-18 


310. Heouravay 


0-13 


252. Coulin(Ewe) . 


0-18 


311. Awe (Inver) 


0'13 


253. a' Chuilinn (Conon) . 


0-18 


312. Auchenreoch . 


0-13 


254. Droma . . 


0-18 


313. Allt na h-Airbhe 


0-13 


255. Borralan . . . . 


0-18 


314. Crogavat .... 


0-13 


256. Martuaham 


0-18 


315. a'Choire .... 


0-13 


257. Beannach (Inver) 


0'18 


316. icColla .... 


0-13 


258. Daimh (Tay) . 


0-17 


317. an Laghair 


0'13 


259. Tearnait .... 


0-17 


318. a' Bhuird. 


0-13 


260. Wester .... 


0-17 


319. Dochard .... 


0-13 


261. an Gead .... 


0-17 


320. na Leitreach . 


0-13 


262. Syre .... 


0-17 


321. Cro Criosdaig . 


0-13 


263. Clousta .... 


0-17 


322. Kennard .... 


0'12 


264. Butterstoue 


0-17 


323. Burga .... 


0-12 


265. Sguod .... 


0-17 


324. Gaol na Doire . 


0-12 


266. a' Bhaid Daraich 


0-17 


325. Builg .... 


0-12 


267. Lindores .... 


0-17 


326. Stormont .... 


0-12 


268. Lundie (Garry) 


0-17 


327. Arthur .... 


0-12 


269. Dornal .... 


0-17 


328. an t-Slagain 


0-12 


270. Urr 


0*17 


329. a' Bhealaich (Alsh) . 


0'12 


271. Tingwall .... 


0-17 


330. Beannach (Gruinard) 


0-12 


272. Derculich .... 


016 


331. Sabiston .... 


0-12 - 


273. an Duin (Spey) 


0-16 


332. Druim Suardalain . 


0-12 


274. Long .... 


0-16 


333. Deoravat .... 


0-12 


275. Forfar .... 


0-16 


334. Monikie (South) 


0-12 


276. Linlithgow 


0-16 


335. Craiglush. 


0-11 


277. Portmore .... 


0-16 


336. Doire nam Mart 


0-11 


278. Whinyeon 


0-16 


337. Ounachan 


O'll 


279. Garlingwark 


0-16 


338. Callater .... 


0-11 


280. a' Mhuilinn 


0-16 


339. Sealbhag .... 


0-11 


281. nam Faoileag . 


0-16 


340. Skeen (Annan). 


0-11 


282. Skiach .... 


0-15 


341. an Duna .... 


0-11 


283. Kilconquhar 


015 


342. na h-Airidh Sleibhe . 


0-11 



STATISTICAL TABLES 

TABLE II continued 



XXV11 



Area. 
Loch. Square 
Miles. 


Loch. 


Area. 
Square 
Miles. 


343. Ederline . . . . O'll 


402. Veiragvat. 


0-08 


344. an Lagain . . . O'll 


403. Burraland 


0'08 


345. Lochinvar 


0-11 


404. Valtos .... 


0'08 


346. Kemp .... 


0-11 


405. an Droighinn . 


0'08 


347. Soulseat . . . . O'll 


406. Rosebery .... 


0'08 


348. an Leoid .... O'll 


407. Balgavies. 


0'08 


349. Raoiuavat . . . O'll 


408. Clickhimin 


0-07 


350. Bosquoy . . . . O'lO 


409. Dochart .... 


0-07 


351. Con(Tay) . . . O'lO 


410. Holl .... 


0'07 


352. Hosta .... 


O'lO 


411. Breaclaich 


0'07 


353. nah-Ealaidh . 


o-io 


412. Burntisland 


0-07 


354. na Ceithir Eileana . 


O'lO 


413. na Lairige 


0-07 


355. Morsgail .... 


o-io 


414. Oban a' Chlachain . 


0'07 


356. Liath .... 


o-io 


415. Shechernich 


0'07 


357. an Laig Aird . 


o-io 


416. na Doire Daraich 


0-07 


358. Phitiiifais 


o-io 


417. Sandy .... 


0-07 


359. Raonasgail 


o-io 


418. nan Gabhar 


0-07 


360. Littlester. 


O'lO 


419. Bad a' Chrotha 


0'07 


361. Bruadale .... 


o-io 


420. a' Chlachain (Lewis . 


0-07 


362. Vatamiip .... 


O'lO 


421. Craggie . . 


0'07 


363. Lunn da-Bhia . 


o-io 


422. AVhiteHeld 


0-07 


364. a' Phearsain 


o-io 


423. Eldrig .... 


0'07 


365. Sloy 


o-io 


424. Monikie (North) 


0'07 


366. Cuil Airidh af Flod . 


O'lO 


425. Gown (North) . 


0'07 


367. nan Lann 


O'lO 


426. Lochnaw .... 


0'07 


368. Eigheach .... 


0'09 


427. Dibadale .... 


0'07 


369. Spynie .... 


0-09 


428. Fleet .... 


0-07 


370. Ghuiragarstidh 


0'09 


429. Airidh na Lie . 


0'07 


371. nam Breac Dearga . 


0'09 


430. Brow .... 


0-07 


372. na Moine Bulge 


0'09 


431. Dhomhmiill Bhig . 


0'07 


373. Cuil na Sithe . 


0'09 


432. Howie. .... 


0'07 


374. a' Chlachain (Nairn) 


0'09 


433. Hoglinns .... 


0'06 


375. Gown (South) . 


0-09 


434. Auchenchapel . 


0'06 


376. Bogtou .... 


0-09 


435. Dallas .... 


0-06 


377. na Sreinge 


0'09 


436. Monzievaird 


0'06 


378. Funds .... 


0'09 


437. Aboyne .... 


0-06 


379. Xorth -house . 


09 


438. Hoil .... 


0'06 


380. Kirk Dam 


0-09 


439. Harperleas 


06 


381. nan Deaspoiit . 


0'09 


440. Moraig .... 


0-06 


382. Muckle Lunga . 


0'09 


441. Fingask .... 


0'06 


383. Aithness . . . . 0'09 


442. an lasgaich 


0'06 


384. na Dei^he fo Dhtas . . 0'08 


443. nan Eun (Tay) 


0'06 


3S5. Sron Smeur . . . 0'08 


444. Tarruinn an Eithir . 


0'06 


386. Hermidale . . . 0'08 


445. na Creige Duibhe 


0'06 


387. na Stainge 


0'08 


446. a' Chonnachair 


0'06 


388. a' Bhradain 


0-08 


447. Mhic' ille Riabhaich 


0-06 


389. Moor Dam 


0'08 


448. Laide .... 


0'06 


390. Leitir Ea<aich . 


0'08 


449. Dhugaill (Torridon) . 


0-06 


391. Lochaber .... 


0'08 


450. Flugarth .... 


0'06 


392. a' Mhiotaiit . 


0-08 


451. Black (Etive) (East) . 


0'06 


393. an Tuirc .... 


0'08 


452. Harrow .... 


0'06 


394. a' Ghlinne Dorcha . 


0-08 


453. Derclach .... 


0'06 


395. Seil 


0-08 


454. Crombie Den . 


0-06 


396. White of My rton . . 0'08 


455. Peerie .... 


0'06 


397. Ceo-Glas . . . . 0'08 


456. Airidh na Ceardaich 


0'06 


398. Leodsay . , . . 1 0'08 


457. Gsinmheich (Xorth) 


0'06 


399. Scaslavat . . . . 0'08 


458. na Bl 


0'06 


400. Tormasacl 


0'08 


459. nan Druimnean 


0'06 


401. Snarravoe 


0'08 


460. Lochenbreck 


0'06 



xxviii THE FRESH-WATER LOCHS OF SCOTLAND 

TABLE II continued 



Loch. 


Area. 
Square 
Miles. 


Loch. 


Area. 
Square 
Miles. 


461. Black (Etive) (Mid) . 


0'05 


512. Tilt 


0'03 


462. ,, ,, (West) 


0-05 


513. Allan .... 


0'03 


463. Buidhe(Tay) . 


0-05 


514. Maol a' Choire . 


0-03 


464. Kinghorn 


0-05 


515. Tutach .... 


0'03 


465. Essan . . . . 


0-05 


516. Mama .... 


0'03 


466. Kirk .... 


0-05 


517. Kirriereoch 


0'03 


467. Bhac .... 


0-05 


518. Brough .... 


0-03 


468. Mill 


0-05 


519. Kilchoan (Lower) . . 0'03 


469. Rae 


0'05 


520. a' Chaoruinn . . . 0'03 


470. nan Garbh Chlachain 


0'05 


521. Hightae Mill . 


0'03 


471. Dubh(Ailort) . 


0-05 


522. Fithie .... 


0'03 


472. na Coinnich 


0'05 


523. Sior 


0-03 


473. Eileach Mhic' ille Riabhaich 


0-05 


524. na Beithe 


0-03 


474. na Garbh-Abhuinn . 


0-05 


525. a' Buaille .... 


0'03 


475. na Claise Fearna 


0'05 


526. Cults .... 


0'03 


476. Baile a' Ghobhainn . 


0'05 


527. na Garbh- Abhuiim Ard . 


0-03 


477. Asta .... 


0-05 


528. Skae .... 


0-03 


478. a' Bhainne 


0'05 


529. Aslaich .... 


0-03 


479. Harelaw .... 


0'05 


530. Dubh (Etive) . 


0-03 


480. Birka .... 


0-05 


531. Hostigates 


0-03 


481. nan Eun (Ness) 


0-05 


532. Duddingston . 


03 


482. an Losgainn Mor 


0-05 


533. Pitlyal .... 


0'02 


483. Dubh-Mor 


0-05 


534. Sand .... 


0-02 


484. Gleann a' Bhearraidh 


0-05 


535. White (Tay) . 


0-02 


485. Fiart .... 


0'05 


536. an t-Seasgain . 


0'02 


486. Edgelaw .... 


0-05 


537. Dubh (Forth) . 


0-02 


487. Grass .... 


0-05 


538. a 5 Chladaich . . . \ 0'02 


488. Lure .... 


0'05 


539. Scoly .... 


02 


489. na Craige .... 


0-04 


540. Crann .... 


0-02 


490. Blairs .... 


0-04 


541. Duartmore . . .0*02 


491. Fender .... 


0-04 


542. Kinellan . . " . . 0'02 


492. Anna .... 


0-04 


543. na Gealaich . . . 0'02 


493. Monk Myre 


0-04 


544. Cornish . . . . 0'02 


494. Eion Mine Alastair . 


0-04 


545. nan Rath . . . 0'02 


495. na Beiste .... 


0-04 


546. Setter . . . . 0'02 


496. nan Geireann . 


0'04 


547. Magillie . . . . 0'02 


497. Beag .... 


0-04 


548. na h' Eaglais . . . 0'02 


498. Kilcheran. 


0-04 


549. Black (Tay) . . . O'Ol 


499. Lundie (Clunie) 


0-04 


550. nan Aiiscot . . . O'Ol 


500. a' Vullan .... 


0-04 


551. Uaine .... O'Ol 


501. Gamhna .... 


0'04 


552. an Tairbeirt Stuadhaich . O'Ol 


502. Uanagan .... 


0'04 


553. Loch on Eilean Subhainn . O'Ol 


503. Collaster .... 


0-04 


554. na Creige Leithe . . O'Ol 


504. Drum lam ford . 


0-04 


555. an Dubh (Lochy) . . O'Ol 


505. Fyntalloch 


0'04 


556. Rainbow .... O'Ol 


506. Kilchoan (Upper) . 


0-04 


557. Dubh (Ness) . . . O'Ol 


507. Ree 


0-04 


558. Choire na Cloich . . O'Ol 


508. Muck .... 


0-04 


559. nan Losganan . . . O'Ol 


509. Geal .... 


0-04 


560. St Margaret's . . . O'Ol 


510. Browster .... 


0-04 


561. Dim (Portsonachan) . 0'003 


511. Bran . . . . 0'04 


562. Allt na Mult . . . 0-003 



STATISTICAL TABLES 



xxix 



TABLE III 

FRESH-WATER LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 

ARRANGED ACCORDING TO MAXIMUM DEPTH 



Loch. 


Max. 
Depth. 
Feet. 


Loch. 


Max. 
Depth. 
Feet. 


1. Morar .... 


1017 


54. Scamadale 


145 


2. Ness .... 


754 


55. Fionn (Gruinard) 


144 


3. Lomond .... 


623 


56. Ba(Mull) 


144 


4. Lochv .... 


531 


57. a' Bhaid-Luachraich 


143 


5. Ericht .... 


512 


58. Eck 


139 


6. Tay 


508 


59. Ossian . 


132 


7. Katrine .... 


495 


60. Lungard ... 


129 


8. Rannoch .... 


440 


61. Tummel . 


128 


9. Treig .... 


436 


62. Laidon , 


128 


10. Sbiel .... 


420 


63. Veyatie .... 


126 


11. Maree .... 


367 


64. Clunie (Ness) . 


123 


12. Glass .... 


365 


65. Cam .... 


122 i 


13. Arkaig .... 


359 


66. na h-Oidhche . 


121 


14. More (Laxford). 


316 


67. a' Bhaid Daraich 


121 


15. Awe (Etive) 


307 


68. Gainmheich (South) . 


120 


16. Earn .... 


287 


69. Eilt 


119 


17. Assynt .... 


282 


70. Achilty .... 


119 


18. Fannich . * . 


282 


71. Tralaig .... 


117 


19. Quoich . 


281 


72. Arienas .... 


116 


20. Mode .... 


270 


73. Nell .... 


115 


21. Monar .... 


260 


74. Dubh-M6r 


114 


22. Muick .... 


256 


75. na h-Airidh Sleibhe . 


113 


23. Fada(Ewe) . 


248 


76. Garry (Tay) . 


113 


24. Atfric .... 


221 


77. Bunacharan 


113 


25. Suainaval 


219 


78. Vennachar 


111 


26. na Sheallag 


217 


79. nan Lann 


109 


27. Laoghal .... 


217 


80. Dhugaill (Torridon i . 


108 


28. Skinaskink 


216 


81. Stack .... 


108 


29. Garry (Ness) . 
30. Damh (Torridon) 


213 
206 


82. Naver .... 
83. Ard 


108 
107 


31. Dim na Seilcheig 


205 


84. Garve .... 


105 


32. Frisa .... 


205 


85. an Duin (Spey) 


102 


33. Mullardoch 


197 


86. Lyon .... 


100 


34. Avich .... 
35. Hope .... 


188 
187 


87. an Laghair 
88. Eilde Mor 


100 
100 


36. Bad a ; Ghaill . 


180 


89. Doon .... 


100 


37. Dhughaill (Carron) . 


179 


90. lush .... 


100 


38. Beannachan 


176 


91. Voil 


98 


39 Laggan .... 


174 


92. Langavat (Lewis) . 


98 


40. a' Chroisg 


168 


93. an t-Seilich 


98 


41. Beinn a' Mheadhoin . 


167 


94. Achray .... 


97 


42. Luichart .... 


164 


95. Drunkie .... 


97 


43. Shin 


162 


96. Daimh (Tay) . 


95 


44. Beoraid .... 


159 


97. Beuisval .... 


95 


45. an Dithreibh . 


157 


98. Raonasgail 


95 


46. Lurgain .... 


156 


99. Dungeon .... 


94 


47. Oich .... 


154 


100. a' Mhnilinn 


94 


48. Dubh (Ailort) . 


153 


101. Garbhaig. 


93 


49. St Mary's 


153 


102. na Creige Duibhe 


93 


50. Owskeich .... 


153 


103. Clair(Ewe) 


93 


51. Coir' an Fhearna 


151 


104. Kernsarv .... 


93 


52. Obisary .... 


151 


105. Nant . . . 


92 


53. Lubnaig .... 


146 


106. a' Bhealaich (Gairloch) . 


92 



XXX 



THE FRESH-WATER LOCHS OF SCOTLAND 

TABLE III continued 



Loch. 


Max. 

Depth. 
Feet. 


Loch. 


Max. 

Depth. 
Feet. 


107. Gorm Loch Mor 


91 


166. an Eilein (Spev) 


66 


108. Seil .... 


91 


167. Brora . 


66 


109. Mhor .... 


91 


168. Doine .... 


65 


110. Fionn (Kirkaig) 


90 


169. lubhair .... 


65 


111. Grunavat. 


90 


170. Benachally 


64 


112. Tarff .... 


89 


171. Bad an Sgalaig . 


64 


113. Dubh (Gruinard) 


88 


172. a' Ghriania 


64 


114. na Leitreach 


88 


173. Loch on Eilean Subhainn . 


64 


115. Baile a' Ghobhainn . 


88 


174. na Meide .... 


63 


116. Tollie .... 


86 


175. Ken .... 


62 


117. Builg .... 


86 


176. Freuchie .... 


62 


118. Calder .... 


85 


177. an Tachdaidh . 


62 


119. na Cuaich 


85 


178. Raoinavat 


61 


120. Merkland 


85 


179. Dibadale .... 


61 


121. a' Ghlinne Dorcha , 


85 


180. Tingwall .... 


60 


122. Oeagach .... 


84 


181. Hunder .... 


60 


123. Tulla .... 


84 


182. a' Choire .... 


60 


124. Calavie .... 


84 


183. na Moine Buige 


60 


125. Leven .... 


83 


184. Kilcheran 


60 


126. Scaslavat .... 


82 


185. Allt na h-Airbhe 


60 


127. na h-Earba (West) . 


81 


186. Gainmheich (North) 


59 


128. Lodh .... 


81 


187. nan Druimnean 


59 


129. a' Chlachain (Nairn) 


80 


188. Lowes (Tweed) 


58 


130. a' Bhealaich (Naver) 


80 


189. Lochrutton 


58 


131. Turret .... 


79 


190. Ederline .... 


58 


132. an Leoid .... 


79 


191. na Beithe 


58 


133. Fender .... 


78 


192. Fiart .... 


58 


134. Menteith .... 


77 


193. Drutnellie 


58 


135. Edgelaw .... 


77 


194. Pattack .... 


58 


136. Chon (Forth) . 


75 


195. Aithness .... 


57 


137. Knockie .... 


75 


196. Ashie .... 


57 


138. Eion Mhic Alastair . 


74 


197. Hoglinns .... 


57 


139. Phitiulais 


74 


198. an Losgainn Mor 


57 


140. Girlsta .... 


74 


199. Clousta .... 


57 


141. Caravat .... 


74 


200. Fleet .... 


56 


142. a' Rhraoin 


73 


201. nan Deaspoirt . 


56 


143. Talla .... 


73 


202. Sealbhag .... 


56 


144. Clings .... 


73 


203. Fada (Gruinard) 


56 


145. Sgamhain 


72 


204. Skiach 


55 


146. Kennard .... 


72 


205. Trool .... 


55 


147. Fiodhaig .... 


71 


206. an t-Slagain . 


55 


148. Crocach .... 


71 


207. Liath .... 


55 


149. 'nam Breac 


71 


208. Kosebery .... 


55 


150., Kilchoan (Upper) 
151. Leitir Easaich . 


70 
70 


209. Mill .... 
210. an Drain c 


55 
55 


152. Alvie .... 


70 


211. Gaol na Doire . 


55 


153. nam Breac Dearga . 


70 


212. Dilate .... 


55 


154. Achall .... 


70 


213. Lochaber .... 


55 


155. Lintrathen 


70 


214. Crogavat .... 


55 


156. Derculich 


70 


215. Gladhouse 


55 


157. Clunie(Tay) . 


69 


216. Eela .... 


55 


158. a' Mhiotailt 


69 


217. Lundie (Garry) 


54 


159. na h-Earba (East) . 


69 


218. Harelaw .... 


54 


160. Ordie .... 


69 


219. Crombie Den . 


53 


161. Grennoch 


68 


220. Lowes (Tay) . 


53 


162. Dubh (Gairloch) 


68 


221. a' Phearsain . 


53 


163. Arklet .... 


67 


222. Gown (South) . 


52 


164. Killin .... 


67 


223. an Daimh (Shin) 


52 


165. na.Beinne Baine 


67 


224. Braigh Horrisdale . 


51 



STATISTICAL TABLES 

TABLE III continued 



XXXI 





Max. 




Max. 


Loch. 


Depth. 


Loch. 


Depth. 




Feet. 




Feet. 


225. Kemp .... 


51 


284. Kindar .... 


41 


226. Leum a' Chlamhain . 


51 


285. Gamhna ... 


41 


227. an Staca .... 
228. Lochindorb 


51 
51 


286. Spiggie .... 
287. White of Myrton . 


41 
40 


229. Mov .... 


50 


288. Craggie .... 


40 


230. Bran .... 


50 


289. Finlas .... 


40 


231. Black (Ryan) . 


50 


290. an Dubh (Lochy) 


40 


232. Inbhir .... 


50 


291. Stacsavat 


40 


233. Arthur .... 


50 


292. Urigill .... 


40 


234. na Craobhaig . 


50 


293. Monzievaird 


39 


235. Scadavay (East) 


50 


294. na Lairige 


39 


236. nan Eun (Tay). 


50 


295. Fadagoa .... 


39 


237. Giorra .... 


49 


296. an Tuirc .... 


39 


238. Migdale .... 


49 


297. nan Aiiscot 


39 


239. Woodhall 


49 


298. Howie .... 


39 


, 240. Ghuilbhm 


49 


299. Burntisland 


39 


241. Morlich .... 


49 


300. Tearnait .... 


39 


242. Coulin (Ewe) . 


49 


301. na Claise Fearna 


38 


243. Gleann a' Bhearraidh 


48 


302. White (Ryan) . 


38 


244. Doire nam Mart 


48 


303. Fad 


38 


245. an Droighinn . 


48 


304. Beannach (Inver) . 


38 


246. Fingask .... 


48 


305. Holl .... 


38 


247. Poulary .... 


47 


306. Kinghorn 


38 


248. Bodavat . 


46 


307. a' Bharpa 


37 


249. Hoil .... 


46 


308. Ghinragarstidh 


37 


250. Birka .... 


45 


309. Scadavay (West) 


37 


251. Fada (X. Uist) 


45 


310. Dee . " . 


36 


252. Meiklie .... 


45 


311. Allt an Fhearna. 


36 


253. Kilchoan (Lower) 


45 


312. Buidhe (Fleet) . 


36 


254. Ree 


44 


313. Black (Etive) (East). 


36 


255. a' Bhealaich (Alsh) . 


44 


314. Skeen (Annan) 


36 


256. Mama .... 


44 


315. a' Bhuird 


36 


257. Expansions of Rivei Dee . 


44 


316. Skae .... 


35 


258. Craiglush 


44 


317. Trealaval. 


35 


259. an Tomain 


44 


318. an Duin (X. Uist) . 


35 


260. Skebacleit 


44 


319. na Beiste .... 


35 


261. Uanagan .... 


43 


320. Loyne (East) . 


35 


262. na Sreiuge 


43 


321. Ussie .... 


35 


263. a' Chuilinn (Conon) . 


43 


322. anXostarie 


35 


264. na h-Eaglais . 


43 


323. Langavat (Benbecula) 


34 


i 265. Doehard .... 


42 


324. Gryfe 


34 


266. Ruthven .... 


42 


325. an Eilein (Gairloch) . 


34 


267. Urr 


42 


326. Ochiltree .... 


34 


268. Skealtar .... 


42 


327. Auchenreoch . 


34 


269. Thorn .... 


42 


328. n a Deighe fo Dheas . 


34 


270. Baddanloch 


42 


329. ic Colla .... 


34 


271. an Laig Aird . 


42 


330. Coire nam Meann 


33 


272. Soulseat .... 


42 


331. Sron Smeur 


33 


273. Bhac .... 


42 


332. Eileach Mhic'illeRiabhaich 


33 


274. na Ceithir Eileanu . 


42 


333. Skerrow .... 


33 


275. Loug .... 


42 


334. Whinyeon 


33 


276. Breaclaich 


41 


335. Urrahag .... 


33 


277. Harperleas 


41 


336. Roer .... 


32 


278. Portmore. 


41 


337. White (Tay) . 


32 


279. Bhradain .... 


41 


338. a' Chlair (Helmsdale) 


32 


280. Heouravay 


41 


339. Deoravat .... 


32 


281. Dubh (Forth) . 


41 


340. Ceo-Glas .... 


32 


282. Hennidale 


41 


341. Hosta .... 


31 


283. Hostigates 


41 


342. Sloy .... 


31 



xxxii THE FRESH- WATER LOCHS OF SCOTLAND 

TABLE III continued 



Loch. 


Max. 
Depth. 

Feet. 


Loch. 


Max. 
Depth. 
Feet. 


343. Druim Suardalain . 


31 


402. Bad a' Chrotha 


23 


344. nan Eun (N. Uist) . 


31 


403. a' Buaille .... 


23 


345. Morsgail .... 


31 


404. Muck .... 


23 


346. Balgavies. 


31 


405. Airidh na Ceardaich 


22 


347. Burga .... 


30 


406. an Stromore ... 22 


348. Chaluim .... 


30 


407. Monikie (North) 


22 


349. an Gead .... 


30 


408. Duartmore 


22 


350. Ba (Tay) .... 


30 


409. nam Faoileag . 


22 


351. Callater .... 


30 


410. Black (Etive) (West) 


22 


352. Harperrig 


30 


411. Cro Criosdaig . 


21 


353. Funds .... 


30 


412. nan Eun (Ness) 


21 


354. Kilbirnie .... 


30 


413. Borralan .... 


21 


355. Forfar .... 


29 


414. Cliff .... 


21 


356. Harrow .... 


29 


415. Gartmorn .... 


21 


357. Martnaham 


29 


416. a' Chaoruinn . 


20 


358. Allan .... 


29 


417. Leodsay .... 


20 


359. an Duna . 


29 


418. na Moracha 


20 


360. Snarravoe 


29 


419. Ohoire na Cloich 


20 


361. na Salach Uidhre . 


29 


420. na Garbh -Abhuinn . 


20 


362. Beag .... 


29 


421. a'Bhaillidh . 


20 


363. Cults .... 


28 


422. Muckle Water . 


20 


364. a' Bhainne 


28 


423. Airidh na Lie . 


19 


365. na h-Achlaise . 


28 


424. Pitlyal .... 


19 


366. Eigheach .... 


28 


425. Oban a' Chlachain . 


19 


367. nan Cuinne 


28 


426. Loyne (West) . 


19 


368. Olubbi Shuns . 


28 


427. Essan .... 


18 


369. a' Ghobhainn . 


28 


428. Dubh (Ness) . 


18 


370. Black (Etive) (Mid) . 


27 


429. an Lagnin 


18 


371. Valtos .... 


27 


430. nan Geireann (Mill) . . 18 


372. nan Geireann . 


27 


431. an t-Seasgain . 


18 


373. Beannach (Gruinard) 


27 


432. Castle (Annan) 


18 


374. a' Chonnachair 


27 


433. Carlingwark 


17 


375. nan Rath 


27 


434. Peppermill 


17 


376. Anna .... 


27 


435. Gown (North) . 


17 


377. a' Vullan .... 


27 


436. Stenness .... 


17 


378. Linlithgow 


27 


437. Auchenchapel . 


17 


379. Muckle Lunga . 


27 


438. Crann .... 


17 


380. an Ruathair . 


26 


439. Threipmuir 


17 


381. Aslaich .... 


26 


440. Vatandip .... 


17 


382. Rainbow .... 


26 


441. Swannay .... 


16 


383. Monikie (South) . . 


26 


442. Rae .... 


16 


384. Drumlamford . 


26 


443. Fitty .... 


16 


385. na Gealaich 


25 


444. Droma .... 


16 


386. na Coinnich 


25 


445. Tutach .... 


16 


387. Lunn da-Bhra . 


25 


446. Kinellan .... 


16 


388. nan Garbh Chlachain 


25 


447. an lasgaich 


16 


389. Vaara .... 


25 


448. Fithie .... 


16 


390. Veiragvat 


25 


449. Lochenbreck 


15 


391. Kirk . 


25 


450. Milton .... 


15 


392. Huna .... 
393. Crunachan 


25 
25 


451. Fyntalloch 
452. Kirriereoch 


15 

15 


394. Butterstone 


25 


453. Moraig .... 


14 


395. Lundie (Clunie) 


25 


454, Whitefield 


14 


396. Strandavat 


25 


455. Sguod .... 


14 


397. Ailsh .... 


24 


456. Ciiil na Sithe . 


14 


398. an Tairbeirt Stuadhaich . 


24 


457. Harray .... 


14 


399. Taruinn an Eithir . 


23 


458. Maberry .... 


14 


400. Rescobie .... 


23 


459. na Stainge 


14 


401. Geal .... 


23 


460. Magillie .... 


14 



STATISTICAL TABLES 

TABLE III continued 



XXX111 



Loch. 


Max. 
Depth. 
Feet. 


Loch. 


Max. 
Depth 
Feet. 


461. na Creige Leithe 


14 


512. Hempriggs 


8 


462. na Crai^e 


13 


513. Dallas .... 


8 


463. HightaeMill . 


13 


514. na h-Ealaidh . 


8 


464. Asta .... 


13 


515. na Moine .... 


8 


465. North-house 


13 


516. Flugnrth .... 


8 


466. Mochrum . . . . 


13 


517. Black (Tay) . 


7 


467. Strom .... 


13 


518. More (Thurso) . 


7 


468. Watten .... 


12 


519. Dliomhnuill Bhig . 


7 


469. Truid air Sgithiche . 


12 


520. Cornish .... 


7 


470. Olavat .... 


12 


521. Eye 


7 


471. Mhic' ille Riabhaich . 


12 


522. Hundland 


7 


472. Syre .... 


12 


523. Shurrery .... 


7 


473. Derelach .... 


12 


524. nan Losganan . 


7 


474. Kinord .... 


12 


525. Araich-Lin 


7 


475. Monk Myre 


12 


526. St John's 


7 


476. Scoly .... 


12 


527. Sandy .... 


7 


477. Drummond 


12 


528. Awe (Inver) . 


7 


478. Castle (Bladenoch) . 


11 


529. na Garbh-Abhuinn Ard . 


7 


479. a' Chlachain (Lewis) . 


11 


530. Tankerness 


7 


480. Brouster .... 


11 


531. Lure .... 


7 


481. Dochart .... 


11 


532. na Bi 


6 


482. Aboyne .... 


11 


533. Moor Dam 


6 


483. Denial .... 


10 


534. Kilconquhar 


6 


484. Uaine . 


10 


535. Grass .... 


6 


485. Oban nam Fiadh 


10 


536. Skene (Dee) . 


6 


486. Dhu (Portsonachan) . 


10 


537. Spynie .... 


6 


487. Eldrig .... 


10 


538. Lochnaw .... 


6 


488. Lindores .... 


10 


539. Kirbister .... 


6 


489. Peerie .... 


10 


540. Braidale .... 


6 


490. Dubh(Etive) . 


10 


541. Brow .... 


6 


491. Burralaiid 


10 


542. Tilt 


5 


492. Duddingston . 


10 


543. Blairs .... 


5 


493. Clickhimin 


10 


544. Scarmclate 


5 


494. Tormasad. 


10 


545. Castle Semple . 


5 


495. Lochinvar ... 10 


546. Heilen .... 


5 


496. Collaster . . . . ' 10 


547. Bosquoy .... 


5 


497. Broom . . . . 9 


548. nan Gabhar 


5 


498. Boardhouse 


9 


549. St Margaret's . 


5 


499. na Doire Daraich 


9 


550. Kirk Dam 


5 


500. Davan .... 


9 


551. Bogton .... 


4 


501. Littlester .... 9 


552. Skaill .... 


4 


502. a' Chladaich . . 9 


553. Sand .... 


4 


503. Con (Tay) ... 9 


554. Brough .... 


4 


504. Cuil Airidh a' Flod . . 9 


555. Sior 


4 


505. Laide ... 9 


556. Stormont. 


3 


506. Gelly . . . . . 9 


557. AlltnaMult . 


3 


507. Achanalt . . . . ! 9 


558. S*biston .... 


3 


508. Shechernich . . . 8 


559. Wester .... 


3 


509. More Barvas . . .8 


560. Ishister .... 


3 


510. Maol a' Choire ... 8 


561. Buidhe(Tay) . 


3 


511. Bradan .... 8 


562. Setter .... 


2 



xxxiv THE FRESH-WATER LOCHS OF SCOTLAND 



TABLE IV 
FRESH-WATER LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 

ARRANGED ACCORDING TO MEAN DEPTH 



Loch. 


Mean 
Depth. 
Feet. 


Loch. 


Mean 
Depth. 
Feet. 


1. Ness .... 


433-02 


53. a' Bhaid Daraich . 


55-60 


2. Morar .... 


284-00 


54. na h-Oidhche . 


53-95 


3. Lochy .... 


228-95 


55. Achilty .... 


51-78 


4. Treig 


207-37 


56. Shin .... 


51-04 


5. Katrine .... 


199-19 


57. Dubh-M6r 


50-93 


6. Tay 


199-08 


58. Eck 


50-16 


7. Ericht .... 


189-21 


59. Bunacharan . . . 


50-11 


8. Rannoch .... 


167-46 


60. Clunie (Ness) . 


49-98 


9. Glass .... 


159-07 


61. Garry (Tay) . 


49-91 


10. Arkaig .... 


152-71 


62. Tummel .... 


48-03 


11. Earn .... 


137-83 


63. Ba(Mull) 


47-42 


12. Shiel .... 


132-73 


64. Eilde Mor 


47-01 


13. More (Laxford) 


125-83 


65. Owskeich .... 


46-90 


14. Maree .... 


125-30 


66. Lyon .... 


44-87 


15. Morie .... 


125-20 


67. na h-Aiddh Sleibhe . 


44-43 


16. Lomond .... 


121'29 


68 Ard 


-13-86 


17. Muick ! 


116-30 


69. Garve .... 


43-60 


18. Fannich .... 


108-76 


70. Lubnaig .... 


42-77 


19. Suainaval. 


108-60 


71. Ossian . 


42-75 


20. Awe (Etive) . 


104-95 


72. na Cuaieh 


42-48 


21. Quoich .... 


104-60 


73. Vennachar 


42-41 


22. na Sheallag . . ' . 


103-47 


74. Dubh (Grninard) 


42 -33 


23. Fada(Ewe) 


102-20 


75. Clair (Ewe) 


42-10 


24. Assynt . 


101-10 


76. Gainmheich (South) . 


41-80 


25. Avich .... 


98-42 


77. Oich .... 


41-78 


26. Monar .... 


98-33 


78. an t-Seilich 


41-30 


27. Affric .... 
28. Dun na Seilcheig 


93-64 

84-00 


79. Tralaig .... 
80. Veyatie .... 


41-03 
41-00 


29. Garry (Ness) . 


78-00 


81. Voil 


40-94 


30. Mullardoch 


77-52 


82. na Leitreach 


40-29 


31. Frisa .... 


76-40 


83. Eion Mhic Alastair . 


39-73 


32. a' Chroisg . ... 


73-78 


84. Daimh (Tay) . 


39-12 


33. St Mary's 


72-93 


85. Naver .... 


39-06 


34. Beoraid . 


72-34 


86. Baile a' Ghobhainn . 


3877 


35. Beannachan 


70-42 


87. Dhugaill (Torridon) . 


38-27 


36. Scamadale 


69 58 




S8'17 


37. Laggan .... 


67-68 


89. Tulla .... 


38-08 


38. Luichart .... 


66-84 


90. Calavie .... 


37-91 


39. Dhughaill (Carron) . 
40. an Dithreibh . 


66-65 
65-93 


91. Cam .... 
92. Insh .... 


37-70 
37-31 


41. Beinn a' Mheadhoin . 


65-36 


93. an Laghair 


37-23 


42. Laoghal .... 


65-21 


94. Eilt 


37-12 


43. Lungard .... 


63-68 


95. nan Lann 


37-03 


44. Dubh(Ailort) . 


62-70 


96. Nell 


36-80 


45. Bad a' Ghaill . 


61-90 


97. Seil 


36-73 


46. Hope .... 


61-47 


98. a' Bhraom 


36-60 


47. Lurgain .... 


60-90 


99. Lowes (Tweed) . 


36-55 


48. Skinaskink 


60-40 


100. Drunkie .... 


36-05 


49. Damn (Tortidon) 


58-91 


101. Achray .... 


36-01 


50. Coir' an Fhearna 


58-79 


102. Stack .... 


35-91 


51. Fionn (Gruinard) 


57-79 


103. an Leoid .... 


35-75 


52. Arienas .... 


56-60 


104. na h-Earba(West) . 


35-62 




1 







STATISTICAL TABLES 

TABLE IV continued 



xxxv 



Loch. 


Mean 
Depth. 
Feet. 


Loch. 


Mean 
Depth. 
Feet. 


105. Garbhaig .... 


35-41 


163. Benachally . . .25*06 


106. Laiclon .... 


35-19 


164. lubhair . . . 24 '96 


107. Talla .... 


3470 


165. Langavat (Lewis) . . 2479 


108. Benisval .... 


34-63 


166. Derculich . . .2472 


109. Scaslavat .... 


34-65 


167. Crogavat . . . .24*66 


110. a'Mhuilinn 


34-15 


168. na Moine Buige . . 24 '62 


111. a' Bhaid-Luachraich 


34-02 


169. Gainmheich (North) . . 24 '50 


112. Creagach .... 


33-17 


170. nam Breac Dearga . . 24 '43 


113. Doine .... 


33-13 


171. Knockie . . . 24 '40 


114. Tollie .... 


33-13 


172. Nant .... 24'31 


115. a' Bhealaioh (Gairloch) . 


3274 


173. Gorm Loch Mor . . 24-30 


116. na Creige Duibhe . . j 32 '49 


174. Arklet .... 24'19 


117. Raonasgail . . . 32 '37 


175. Killin . . . .24-15 


118. Keuuard .... 


32-27 


176. Mhor .... 24*11 


119. Turret .... 


3179 


177. Tarff .... 23 '89 


120. Fender .... 


31-77 


178. Dilate .... 23-50 


121. Dubh (Gairloch) 


31-74 


179. Lintrathen . . . 23 '42 


1-22. Girlsta .... 


31-41 


180. Black (Ryan) . . . 23 '37 


123. a' Bhealaich (Naver) 


31-20 


181. Ederline ... . 23*15 


124. na h-Earba (East) . 


31-11 


182. Phitiulais. . . . 23 '15 


125. Edgelaw .... 


31-10 


183. Fiart . . . . ; 23 '13 


126. an Duin (Spey) 


30-38 


184. Gaol na Doire . . . 23 '04 


127. a' Mhiotailt '. 


30-30 


185. nah-Eaglais . . . 22 "84 


! 128. Allt na h-Airbhe 


30-17 


186. Fiugask .... 


22 83 


129. Merkland 


30-14 


187. Freuchie .... 22 '83 


130. a' Chlachain (Nairn) 


29-84 


188. Harelaw .... 22 '83 


131. Loch on Eilean Subhainn . 


29-70 


189. Brora .... 22'68 


132. Kilchoan (Upper) 


29-54 


190. Dungeon .... 22'64 


133. Chon (Forth) . 


29-38 


191. Liath .... 22'36 


134. Loch .... 


29-22 


192. Meiklie .... 


22*10 


135. Drumellie 


29-18 


193. Fleet .... 


21-81 


136. Chmie(Tay) . . . 29'12 


194. Giorra .... 


2170 


137. Grunavat . . .28*36 


195. nan Eun (Tay) . 


21-64 


138. na Beinne Baine . . 28 '33 


196. Doire nam Mart 


21*33 


139. a' Ghriama . . . 28 '03 


197. Ashie .... 


21*26 


140. nam Breac . . . 27 '94 


198. Migdale .... 


21-18 


141. Achall .... 


27-83 


199. Kilcheran 


21*11 


142. Dibadale .... 


2777 


200. Ken 


21-00 


143. Builg .... 27-75 


201. Calder .... 


20-87 


144. na Beithe . . . 27 '72 


202. nan Deaspoirt . 


20-82 


145. a' Ghlinne Dorcha . . 27 '65 


203. Grennoch .... 


20-82 


146. a' Choire .... 


27-55 


204. Dubh (Forth) . 


2070 


147. an Daimh (Shin) 


27-17 


205. Sealbhag .... 


20-66 


148. Alvie . . . . 27'02 


206. na Meide .... 


20*61 


149. Sgamhain . . .26*77 


207. Lochaber .... 


20-57 


150. Doon .... 26*71 


208. Raoinavat 


20-56 


151. Clings . . . 26 '55 


209. Fionn .... 


20-40 


152. Ordie .... 


26-32 


210. Lowes (Tay) . 


20-40 


153. Kemp . . . . j 26 '23 


211. Kilchoan (Lower) 


20-30 


154. Hoglinns . . . . 26'09 


212. Leitir Easaich . 


19-90 


155. an Drainc . . . 25 '86 


213. Menteith. . . . 1977 


156. Fiodhaig . . . .2579 


214. Woodhall . . . 19 '67 


157. Arthur .... 25 -77 


215. Leum a' Chlarnhain . . 19'54 


158. Obisary . . . .2570 


216. a' Phearsain . . . ; 19 '44 


159. an Eilein (Spey) . . 25 '47 


217. Mov . . . .19-31 


160. Mill .... 25-33 


218. Thorn . . . 19 '25 


161. Bad an Sgalaig . . 25'26 


219. Hoil .... 19-09 


162. Rosebery .... 25 '20 


220. Tingwall .... 


18-88 



xxxvi THE FRESH- WATER LOCHS OF SCOTLAND 

TABLE IV continued 



Loch. 


Mean 
Depth. 
Feet. 


Loch. 


Mean 
Depth. 
Feet. 


221. Aithness .... 


18-84 


279. Eileach Mhic' ille Riabhaich 


14-13 


222. an Losgaiun Mor 


18-65 


280. Breaclaich 


14-09 


223. Trool .... 


18-39 


281. White (Ryan) . 


14-09 


224. Coulin (Ewe) . 


18-29 


282. Pattack .... 


14-07 


225. Braigh Horrisdale . 


18-10 


283. Expansions of River Dee . 


13-90 


226. Skiach .... 


18-09 


284. na Ceithir Eileana . 


13-81 


227. Hunder .... 


18-08 


285. White of Myrton 


13-70 


228. Harperleas 


17-88 


286. a' Chlalr (Helmsdale) 


13-65 


229. an Tachdaidh . 


17-88 


287. Monikie (South) 


13-47 


230. Skeen (Annan) . 


17-87 


288. Vaara .... 


13-44 


231. Crornbie Den . 


17-64 


289. Black (Etive) (East) . 


13-39 


232. na Sreinge 


17-53 


290. an Ruathair 


13-34 


233. Stacsavat. 


17-43 


291. Ghuilbinn 


13-32 


234. Gryfe .... 


17-35 


292. i) a Claise Fearna 


13-23 


235. Baddanloch 


17-33 


293. Beannach (Inver) 


13-20 


236. Fada (Gruinard) 


17-15 


294. an Diina .... 


13-12 


237. Fad 


17-13 


295. Udgill 


13-10 


238. Holl .... 


17-04 


296. Lochrutton 


13-03 


239. Crocach .... 


16-80 


297. White (Tay) . 


12-95 


240. Uanagan .... 


16-80 


298. Gleann a' Bhearraidh 


12-79 


241. nan Auscot 


16-79 


299. Anna .... 


12-74 


242. Portmore .... 


16-79 


300. Burga . . - . 


12-65 


243. na Craobhaig . 


16-63 


301. Bran 


12-63 


244. Eela 


16-59 


302. Skerrow .... 


12-63 


245. Caravat .... 


16-57 


303. Bodavat .... 


12-61 


246. a' Bhealaich (Alsh) . 


16-53 


304 a' Ghobhainn . 


12-59 


247. Bhac .... 


16-50 


305. Monikie (North) 


12-58 


248. an Toraain 


16-47 


306. Snarravoe 


12-55 


249. Gladhouse 


16-46 


307. Hermidale 


12-49 


'. 250. an t-Slagain 


16-42 


308. Hosta .... 


12-47 


251. Lundie (Garry) 


16-28 


309. a' Bharpa .... 


12-43 


252. Hostigates 


16-26 


310. Lochindorb 


12-42 


253. Tearnait .... 


16-16 


311. nan Cuinne 


12-38 


254. Craiglusli. 


16'13 


312. Morsgail .... 


12-33 


255. Skealtar .... 


15-90 


313. a' Vullan .... 


12-27 


256. Gown (South) . 


15-88 


314. Whinyeon 


12-22 


257. Howie .... 


15-69 


315. Urr .' 


12-06 


258. nan Druimnean 


15-61 


316. Callater .... 


11-99 


259. an Staca . 


15-52 


317. Burntisland 


11-85 


260. an Dubh (Lochy) . 


15-50 


318. Dochard .... 


11-84 


261. Kinghorn. 


15-33 


319. Birka .... 


11-81 


262. Craggie .... 


15-31 


320. Beag .... 


11-80 


263. Clousta .... 


15-27 


321. Buidhe (Fleet) . 


11-72 


264. Skebacleit 


15-21 


322. Fadagoa .... 


11-70 


265. Soulseat .... 


15-19 


323. Auchenreoch . 


11-69 


266. an Laig Aird . 


15-12 


324. Harrow .... 


11-61 


267. Ree ..... 


14-96 


325. Coire nam Meann 


11-60 


268. Leven .... 


14-87 


326. Deoravat .... 


11-60 


269. Bhradain .... 


14-83 


327. Spiggie .... 


11-59 


270. an Droighinn . 


14-78 


328. Urrahag .... 


11-49 


271. Monzievaird 


14-70 


329. Forfar .... 


11-43 


272. Morlich .... 


14-62 


330. an Gead .... 


11-29 


273. an Eilein (Gairloch) . 


14-39 


331. Butterstone 


11-29 


274. Rainbow .... 


14-33 


332. Black (Etive) (Mid) . 


11-27 


275. Allt an Fhearna 


14-31 


333. Ruthven .... 


11-27 


276. Mama .... 


14-29 


334. Muckle Water . 


11-08 


277. Dee 


14-25 


335. na Lairige 


10-97 


278. Kindar .... 


14-22 


336. Harperrig 


10-96 



STATISTICAL TABLES 

TABLE IV continued 



XXXVll 



Loch. 


Mean 
Depth. 
Feet. 


Loch. 


Mean 
Depth. 
Feet. 


337. an Nostarie 


10-95 


395. Peppernrill 


8-60 


338. Aslaich .... 


10-91 


396. Castle (Annan) 


8-58 


339. Drumlamford . 


10-82 


397. nan Geireann . 


8-47 


340. ic Colla .... 


10-77 


398. Limn da-Bhra . 


8-44 


341. Gartmorn 


1075 


399. Watten .... 


8-42 


342. Cliff 


10-65 


400. Pitlyal .... 


8-32 


343. an Tuirc .... 


10-60 


401. Ailsh .... 


8-30 


344. na Beiste .... 


10-56 


402. Auchenchapel . 


8-26 


345. na Deighe fo Dheas . 


10-54 


403. nan Rath .... 


8-23 


346. an Tairbeirt Stuadhaich . 


10-50 


404. Huna .... 


8-22 


347. Stenness .... 


10-43 


405. Langavat (Benbecula) 


8-12 


348. a'Bhuird. . . . 1 10 '42 


406. Sloy .... 


8-12 


349. Allan . . . . 10 '40 


407. Ba (Tav) .... 


8-10 


350. Geal . . . .10'38 


408. Whitefield 


8-01 


351. Loyne (East) . . . 10 '32 


409. Ussie .... 


7-98 


352. Sron Smeur . . . 10 '31 


410.' Chaluim .... 


7-92 


353. Druim Suardalain . . 10 '30 


411. Threipmuir 


7-90 


354. Fada(X. Uist) . . . 10 -25 


412. Inbhir .... 


7-85 


355. a' Chuilinn (Conon) . . 10'22 


413. nan Eun (N. Uist) . 


7-84 


356. Funds . . . . 10-20 


414. Lundie (Clunie) 


7-80 


357. Roer . . . .10-16 


415. Crunachan 


7-79 


358. Ceo-Glas . . . .10-14 


416. Oehiltree .... 


7'68 


359. Rescobie ' 


9-99 


417. Lochenbreck 


7-61 


360. Kirk .... 


9-96 


418. a' Bhaillidh . 


7-60 


361. na Gealaich 


9-94 


419. an Lagain 


7-57 


362. Long .... 


9-92 


420. Linlithgow 


7-55 


363. nan Eun (Ness) 


9-90 


421. Fyntalloch 


7-48 


364. Poulary .... 


9-90 


422. i) a Craige .... 


7-42 


365. Vatandip .... 


9-85 


423. Cuil na Sithe . 


7-42 


366. Balgavies .... 


9-76 


424. Derclach .... 


7-42 


367. Oban a' Chlachaiu . 


9-75 


425. Fithie .... 


7-42 


368. Kilbirnie .... 


972 


426. Fitty .... 


7-40 


369. a' Bhainne 


9-69 


427. Valtos .... 


7-40 


370. Finlas .... 


9-69 


428. Leodsay .... 


7-38 


371. Martnaham 


9-61 


429. Heouravay 


7-37 


372. Borralan .... 


9-60 


430. Black (Etive) (West) 


7-34 


373. na h-Achlaise . 


9-58 


431. Maberry .... 


7-32 


374. Gamhna .... 


9-56 


432. HightaeMill . 


7-31 


375. Skae .... 


9-52 


433. nan Garbh Chlachain 


7-28 


376. Choire na Cloich 


9-44 


434. Kinellan .... 


7-14 


377. a' Chaoruinn . 


9-37 


435. Muck .... 


7-12 


378. na Moracha 


9-26 


436. Dubh (Ness) . 


7-00 


379. Swannay .... 


9-22 


437. na Creige Leithe 


7-00 


380. Trealaval .... 


9-22 


438. Strom .... 


7-00 


381. Airidli na Lie . 


9'21 


439. Kirriereoch 


6-98 


382. Cults .... 


9-16 


440. Sguod .... 


6-91 


383. Scadavay (West) 


9'16 


441. Muckle Lunga . 


6-88 


384. Ghiuragarstidh 


9-08 


442. Gown (North) . 


6-87 


385. Han-ay .... 


9-02 


443. Carlingwark . 


6-86 


386. an Stromore 


9-01 


444. a' Buaille .... 


6-82 


387. a' Chonnachair . . . I 8 '88 


445. Essan .... 


6-82 


388. Clubbi Shuns . 


8-85 


446. Crann .... 


679 


389. Cro Criosdaig . 


8-80 


447. Mochrum .... 


6-75 


390. nam Faoileag . 


8-69 


448. Milton .... 


6-67 


391. Veiragvat 


8-68 


449. North-house . 


6-60 


392. Scadavay (East) 


8-67 


450. Rae 


6-59 


393. naCoinnich . 


8-62 


451. Castle (Bladenoch) . 


6-56 


394. Strandavat 


8-61 


452. na Salach Uidhre 


6-54 



xxxviii THE FRESH- WATER LOCHS OF SCOTLAND 

TABLE IV continued 



Loch. 


Mean 
Depth. 
Feet. 


Loch. 


Mean 
Depth. 
Feet. 


453. Beannach (Gruinard) 


6-45 


508. Achanalt .... 


4-50 


454. Lochinvar 


6-41 


509. a'Chladaich . 


4-50 


455. nan Geireann (Mill) . 


6'37 


510. Cuil Airidh a' Flod . 


4'50 


456. Tarruin an Eithir 


6-37 


511. St John's 


4-50 


457. Peerie .... 


6-34 


512. Bruadale .... 


4'46 


458. an Duin (N. Uist) . 


6-27 


513. Araich-Lin 


4-45 


459. Droma .... 


6-27 


514. Bradan .... 


4-40 


460. Eigheach .... 


6-09 


515. Shurrery .... 


4-37 


461. Bad a' Chrotha 


6-08 


516. Tankerness 


4-35 


462. Boardhouse 


6-06 


517. More Barvas 


4-33 


463. Aboyne .... 


6-03 


518. Hundland 


4-32 


464. Loyne(West) . 


5-93 


519. Lochnaw .... 


4-32 


465. Duartmore 


5-90 


520. Oban nam Fiadh 


4-23 


466. Collaster .... 


5-88 


521. Olavat .... 


4-20 


467. Airidh na Ceardaicli . 


5-86 


522. More (Thurso) . 


4-18 


468. Truid air Sgithiche . 


5-83 


523. Kirbister .... 


4-15 


469. an t-Seasgain . 


572 


524. Eye 


4-06 


470. Scoly .... 


5*72 


525. Shechernich 


4-01 


471. Eldrig .... 


5-70 


526. Da van .... 


3-98 


472. Clickhimin 


5'60 


527. Dhomhnuill Bhig . 


3-90 


473. Torniasad. 


5-60 


528. Lure .... 


3-90 


474. Brouster .... 


5-57 


529. Kilconquhar 


3-90 


475. an lasgaich 


5-55 


530. Cornish .... 


3'80 


476. Moraig .... 


5-54 


531. na Doire Daraich 


3-60 


477. a' Chlachain (Lewis) . 


5-52 


532. Dallas .... 


3-50 


478. Syre .... 


5-48 


533. nan Losganan . 


3'50 


479. Magillie .... 


5-37 


534. Uaine .... 


3-50 


480. Dornal .... 


5-36 


535. Con (Tay) 


3-47 


481. Mhic' ille Riabhaich. 


5-35 


536. na Bi . .' . 


3-30 


482. Flugarth .... 


5-23 


537. Moor Dam 


3-27 


483. Hempiiggs 


5-22 


538. na Garbh-Abhuinn Ard . 


3-02 


484. Laide .... 


5-16 


539. Grass .... 


2-99 


485. Duddingston 


5-14 


540. Dubh (Etive) . 


2-76 


486. Asta .... 


5-11 


541. Spynie .... 


2-71 


487. Maol a' Choire . 


5-10 


542. Blairs .... 


2-55 


488. na Stainge 


5-10 


543. Brow .... 


2-50 


489. Drummond 


5-09 


544. Bosquoy .... 


2-50 


490. Monk Myre 


5-08 


545. Castle Semple . 


2-50 


491. Lindores .... 


5-06 


546. Heileri .... 


2-50 


492. Gelly .... 


5-03 


547. nan Gabhar 


2 '50 


493. Kinord .... 


5-03 


548. St Margaret's . 


2-50 


494. Dochart .... 


r >-02 


549. Scarmclate 


2-50 


495. Broom .... 


5-02 


550. Tilt .... 


2-50 


496. Dhu (Portsonachan) . 


5-00 


551. Bogton .... 


2-00 


497. Kirk Dam 


5-00 


552. Brough .... 


2-00 


498. Tutach . 


4-88 


553. Sand .... 


2-00 


499. Awe (Inver) 


4-80 


554. Sior 


2-00 


500. Sandy .... 


4-76 


555. Skaill .... 


2-00 


501. Black (Tay) . 


473 


556. Allt na Mult . 


1-50 


502. Skene(Dee) . 


4-69 


557. Buidhe(Tay) . 


1-50 


503. Burraland 


4-67 


558. Isbister .... 


1-50 


504. na h-Ealaidh . 


4-66 


559. Sabiston .... 


1-50 


505. na Garbh-Abhuinn . 


4-65 


560. Stormont .... 


1-50 


506. na Moine .... 


4-61 


561. Wester .... 


1-50 


507. Littlester. 


4-55 


562. Setter .... 


1-00 











STATISTICAL TABLES 



xxxix 



TABLE V 

FRESH-WATER LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 
ARRANGED ACCORDING TO VOLUME OF WATER 





Volume 




Volume 




in 




in 


Loch. 


Million 


Loch. 


Million 




Cubic 




Cubic 




Feet. 




Feet. 


1. Ness 


263,162 


53. Boon .... 


1,517 


2. Lomond 


92,805 


54. Beinu a' Mheadhoin . 


1,435 


3. Morar .... 


81,482 


55. an Dithreibh . 


1,366 


4. Tay 


56,550 


56. Tummel .... 


1,317 


5. Awe (Etive) 


43,451 


57. Ossian . 


1,224 


6. Maree .... 


38,539 


58. Tulla .... 


1,167 


7. Ericht .... 


38,027 


59. Beoraid .... 


1,156 


8. Lochy .... 


37,726 


60. Ard 


1,150 


9. Rannoch 


34,387 


61. Lnbnaig 


1,144 


10. Shiel .... 


27,986 


62. Mhor .... 


1,134 


11. Katrine .... 


27,274 


63. Cam .... 


1,063 


12. Arkaig . 


26,573 


64. Veyatie . 


1,062 


13. Earn .... 


14,421 


65. Arienas .... 


1,035 


14. Treig .... 


13,907 


66. Voil . 


1,000 


15. Shin .... 


12,380 


67. Stack .... 


988 


16. Fannich . 


10,920 


68. Harray .... 


951 


17. Assynt . 


8,731 


69. Oich .... 


890 


18. Quoich .... 


8,345 


70. Garry (lay) . 


846 


19. Glass .... 


8,265 


71. Owskeich 


846 


20. Fionn (Gruinard) 


5,667 


72. Obisary 


837 


21. Lairgan .... 


5,601 


73. Dhughaill (Carron) . 


823 


22. More (Laxford) 


4,928 


74. Beannachan 


819 


23. Laoghal 


4,628 


75. na h-Oidhche . 


816 


24. Dun na Seileheig 


4,599 


76. Ken .... 


792 


25. Fada(Ewe) . 


4,091 


77. Calder .... 


767 


26. Hope .... 


4,032 


78. Garve .... 


721 


27. ua Sheallag 


3,948 


79. Stenness 


716 


28. Garry (Ness) . 


3,794 


80. Eilt .... 


686 


29. Frisa .... 


3,603 


81. Scamadale 


685 


30. Skinaskink 


3,518 


82. a' Bhraoin 


669 


31. Avich .... 


3,327 


83. Lungard 


599 


32. Luichart . . 


3,288 


84. Merkland 


577 ; 


33. Monar .... 


3,213 


85. Menteith 


562 


34. Morie 


3,201 


86. Brora .... 


553 


35. Suainaval 


2,843 


87. Nell .... 


515 


36. Muick .... 


2,771 


88. na Meide 


498 


37. Mullardoch 


2,553 


89. EildeMor 


493 


38. Naver 


9 461 


90. a' Bhaid-Luachraich 


486 


39. Langavat (Lewis) 


2,388 


91. Baddanlocb 


479 


40. Eck . . . . ! 


2,381 


92. Grunavat 


478 


41. Leven .... 


2,195 


93. Lyon .... 


461 


42. Damh (Torridon) 


2,183 


94. Insh .... 


454 


43. Aftric .... 


2,146 


95. an t-Seilich 


448 


44. Lurgain . 


2,140 


96. a' Chlair (Helmsdale) 


446 


45. a' Chroisg . . . : 


2,057 


97. Talla .... 


443 


46. St Mary's 


2,018 


98. Creagach 


429 


47. Vennachar . . . 


1,903 


99. Fiodhaig 


415 


48. Coir' an Fhearna 


1.886 


100. na h-Earba ( West) . 


408 


49. Bad a' Ghaill . 


1,768 


101. Lintrathen 


405 


50. Laidon 


1,762 


102. Achall .... 


401 


51. Ba i Mull 


1,602 


103. a' Bhealaich (Gairloch) 


398 


52. Clunie(Ness) . 


1,533 


104. nan Cuinne 


396 



xl THE FRESH- WATER LOCHS OF SCOTLAND 

TABLE V continued 





Volume 




Volume 




in 




in 


Loch. 


Million 


Loch. 


Million 




Cubic 




Cubic 




Feet. 




Feet. 


105. Dubh (Gruinard) 


374 


162. Lowes (Tweed) 


157 


106. Chon (Forth) . 
107. Freuchie .... 


358 
347 


163. Moy .... 
164. Fadagoa .... 


157 
156 


108. Bunacharan 


343 


165. Trealaval 


156 


109. Watten . 


341 


166. Bad an Sgalaig 


151 


110. Kernsary 


333 


167. a' Mhuilinn 


150 


111. Achilty . 


332 


168. Boardhouse 


150 


112. Achray .... 


321 


169. Black (Ryan) . 


149 


113. a' Ghriama 


314 


170. Crocach . 


148 


114. Ashie .... 


309 


171. Nant .... 


148 


115. Girlsta .... 


308 


172. lubhair . 


147 


116. Scadavay (West) 


306 


173. na Leitreach . 


147 


117. an Ruathair . 


304 


174. Hundcr . . 


146 


118. Leum a' Chlamhain . 


298 


175. Dilate .... 


145 


119. Lochindorb 


291 


176. an Eilein (Spey) 


144 


120. Clair(Ewe) 


287 


177. Woodhall . 


144 


121. Urigill . 


285 


178. Killin .... 


137 


122. Thorn ... 


277 


179. Dubh (Gairloch) 


136 


123. Calavie .... 


276 


180. Tarff .... 


136 


124. a' Bhaid Daraich 


270 


181. an Laghair 


135 


125. Caravat .... 


270 


182. an Duin (Spey) 


134 


126. Gladhouse 


269 


183. Ordie .... 


133 


127. Tralaig .... 


267 


184. Allt an Fhearna 


132 


128. Grennoch 


263 


185. Fad .... 


132 


129. Expansions of River Dee . 


261 


186. na h-Alridh Sleibhe . 


131 


130. Benisval .... 


260 


187. Skebacleit 


128 


131. Gainmheich (South) . 


246 


188. Loyne (East) . 


123 


132. Tollie .... 


244 


189. nan Geireann (Mill) . 


121 


133. Migdale . 


242 


190. Cliff .... 


118 


134. Swannay 


242 


191. Trool .... 


116 


135. a' Bhealaich (Naver) 


238 


192. anLeoid. 


136. Garbhaig 


228 


193. nan Eun (N. Uist) . . 114 


137. Turret .... 222 


194. Scadavay (East) . . 112 


138. Arklet .... 


222 


195. Spiggie . . . . HI 


139. Drumellie 


222 


196. Allt na h-Airbhe . . HO 


140. Drunkie .... 217 


197. an Staca .... 


110 


141. na Cuaich 


214 


198. Fada (Gruinard) 


109 


142. Ba(Tay). 


206 


199. an Drainc 


108 


143. an Daimh (Shin) 


205 


200. Derculich . . . 108 


144. Fada (N. Uist) 


199 


201. Harperrig ... 108 


145. Doine .... 


196 


202. Kennard .... 


108 


146. Gorm Loch Mor 


196 


203. Pattack .... 


106 


147. Knockie .... 


194 


204. Kilbirnie 


105 


148. Lowes (Tay) . 


194 


205. nan Lann . . . 105 


149. Meiklie .... 


193 


206. Urrahag . 105 


150. Morlich .... 


192 


207. a' Choire . . .103 


151. na h-Earba (East) . 


191 


208. Eela . . . . 103 


152. Daimh (Tay) . 


190 


209. Loch . . 


103 


153. na Beinne Baiue 


190 


210. Clings . 


101 


154. Fionn (Kirkaig) 


186 


211. Strom .... 


101 


155. Ruthven .... 


180 


212. Raonasgail 


94 


156. Benachally 


178 


213. Builg .... 


93 


157. nam Breac 


172 


214. na Craobhaig ... 93 


158. Clunie (Tay) . 
159. Sgamhain 


170 
165 


215. White (Ryan) . 
216. Coulin (Ewe) . 


92 

90 


160. Alvie .... 163 


217. Crogavat 


90 


161. Dee 


157 


218. Skealtar 


90 



STATISTICAL TABLES 

TABLE V continued 



xli 



Loch. 


Volume 
iu 
Million 
Cubic 
Feet. 


Loch. 


Volume 
in 
Million 
Cubic 
Feet. 


219. Ailsh .... 


88 


276. Muckle Water . 


57 


Dubh (Ailort) . 


87 


277. a' Bhealaich (Alsh) . 


56 


221. Dungeon 


87 


278. Maberry 


56 


222. Gryfe .... 


87 


279. Whinyeon 


56 


223. Tingwall 


87 


280. Urr " . 


56 


224. Ghuilbinn 


85 


281. an t-Slagain . 


55 


225. Giorra .... 


84 


282. Baile a' Ghobhainn . 


55 


226. Arthur .... 


83 


283. a' Ghobhainn . 


54 


227. Kindar .... 


83 


284. an Gead 


54 


228. Vaara .... 


80 


285. Butterstone . 


53 


229. Sell .... 


79 


286. Skeen (Annan) 


53 


230. a' Chlachain (Nairn) 


78 


287. a' Phearsain . 


52 


231. Lundie (Garry) 


78 


288. na Creige Duibhe . 


52 


232. Gaol na Doire . 


77 


289. Ochiltree. 


52 


233. Kemp .... 


77 


290. Dibadale 


51 


234. Skiach .... 


77 


291. Forfar .... 


51 


235. na h-Achlaise . 


76 


292. Hundland 


51 


236. Portmore 


76 


293. a' Chuilinn (Conon) . 


50 


237. Tearnait 


75 


294. Bodavat .... 


50 


238. Lochrutton 


73 


295. Inbhir .... 


50 


239. Scaslavat 


73 


296. nan Deaspoirt . 


50 


240. an Tachdaidh-. . . 72 


297. Borralan 


49 


241. Castle (Annan) . . 72 


298. Craiglush 


49 


242. Clousta . 71 


299. Hempriggs 


49 


243. Ederline .... 70 


300. Straudarat 


49 


244. na Salach Uidhre 


70 


301. Huna 


48 


245. a' Mhiotailt . 


69 


302. Edgelaw 


47 


246. an Tomain ... 69 


303. Lochaber 


47 


247. Rescobie .... 


69 


304. Martnaham . 


47 


248. Buidhe (Fleet) 


68 


305. Soulseat 


47 


249. Mochram ... 68 


306. Truid air Sgithiche . 


47 


250. Skerrow . . . > 68 


307. Aithness 


46 


Ussie .... 68 


308. Fitty .... 


46 


252. Beannach (luver) . .67 


309. Eion Mhic Alastair . 


45 


253. Doire nam Mart . . 67 


310. Leitir Easaich . 


45 


254. Phitiulais ... 67 


311. Milton .... 


45 


' 255. a' Bharpa ... 66 


312. More Barvas . 


45 


256. Dubh-M6r ... 66 


313. an Laig Aird . 


44 


257. Stacsavat ... 66 


314. an Nostarie 


44 


258, Threipmuir ... 66 


315. Anchenreoch . 


44 


259. Castle (Bladenoch) . . 65 


316. Dochard .... 


44 


260. Gartmorn ... 65 


317. Hoglinns 


44 


261. Raoinavat ... 65 


318. Langavat (Benbecula) 


44 


262. Dhugaill (Torridon) . 63 


319. Burga .... 


43 


263. Braigh Horrisdale . . 62 


320. Gainmheich (North) 


43 


2o4. Liath .... 62 


321. Monikie (South) 


43 


265. a' Bhaillidh . . .61 


322. na Sreinge 


43 


266. an Stromore ... 61 


323. Koer .... 43 


267. Sealbhag . . . j 61 


324. Shurrery ... 43 


268. a' Ghlinne-Dorcha . . 60 


325. an Diina ... 41 


269. Coire nam Meann . .60 


326. Fleet .... 41 


270. nam Breac Dearga . 


60 


327. Kinord .... 41 


271. Skene(Dee) . 


60 


328. Kirbister . . . 41 


272. na Moine Buige 


59 


329. Loyne (West) . . . ! 40 


273. an Eilein (Gairloch) . 


58 


330. na Moracha . . . 1 39 


274. Finlas .... 


58 


331. Poulary . . . .39 


275. Rosebery 


58 


332. Callater .... 38 



xlii THE FRESH-WATER LOCHS OF SCOTLAND 

TABLE V continued 



Loch. 


Volume 
in 
Million 
Cubic 
Feet. 


Loch. 


Volume 
in 
Million 
Cubic 
Feet. 


333. Deoravat 


38 


390. Monzievaird . 


24 


334. Gown (South) . 


38 


391. na Deighe fo Dheas . 


24 


335. ic Colla .... 


38 


392. an Lagain 


23 


336. na Ceithir Eileana . 


38 


393. Araich-Lin 


23 


337. nam Faoileag . 


38 


394. Crunachan 


23 


338. St John's 


38 


395. Ghuiragarstidh 


23 


339. a'Bhuird 


37 


396. Lunn da-Bhra . 


23 


340. Eye .... 


37 


397. na Beithe 


23 


341. Hosta .... 


36 


398. na Lairige 


23 


342. Mill .... 


36 


399. Sloy .... 


23 


343. Druim Suardalain . 


35 


400. Sron Smeur 


23 


344. Morsgail .... 
345. an Diiin (N. Uist) . 


35 
34 


401. Balgavies 
402. Beannach (Gruinard) 


22 
22 


346. Bhradain 


34 


403. Bhac .... 


22 


347. Fiart .... 


34 


404. Burntisland 


22 


348. Linlithgow 


34 


405. Castle Semple . 


22 


349. nan Eun (Tay) 


34 


406. Black (Etive) (East) . 


21 


350. Peppermill 


34 


407. Heilen .... 


21 


351. Chaluim .... 


33 


408. Scarmclate 


21 


352. Holl .... 


33 


409. Drummond 


20 


353. an Droighinn . 
354. Droma .... 


32 
32 


410. Kinghorn 
411. na Claise Fearna 


20 
20 


355. Fingask .... 


32 


412. Oban a' Chlachain . 


20 


356. Gelly .... 


32 


413. Veiragvat 


20 


357. Long .... 


32 


414. Airidh na Lie . 


19 


358. More (Thurso) 


32 


415. Broom .... 


19 


359. Sguod .... 


32 


416. Cuil na Sithe . 


19 


360. Achanalt 


31 


417. Eileach Mhic' ille Riabhaich 


19 


361. Carlingwark . 


31 


418. Harrow .... 


19 


362. Cro Criosdaig . 


31 


419. Lochinvar 


19 


363. Crombie Den . 


31 


420. Awe (Inver) 


18 


364. Fender .... 


31 


421. na Moine 


18 


365. Harperleas 


31 


422. Uanagan ' 


18 


366. Howie .... 


31 


423. Black (Etive) (Mid) . . 17 


367. White of Myrton 


30 


424. Muckle Lunga . . . 17 


368. Craggie .... 


30 


425. Oban nam Fiadh 


17 


369. Harelaw .... 


30 


426. Ree .... 


17 


370. Hermidale 


29 


427. Whitefield 


16 


371. Hoil .... 


29 


428. Bradan .... 


16 


372. Kilchoan (Upper) . 
373. Tankerness 


29 
28 


429. Eigheach 
430. Gleann a' Bhearraidh 


16 
16 


374. an Losgainn Mor 


27 


431. Kilchoan (Lower) . .16 


375. Breaclaich 


27 


432. Kilconquhar . 


16 


376. Snarravoe 


27 


433. Leodsay 


16 


377. Vatandip 


27 


434. North-house . 


16 


378. Dornal .... 


26 


435. Valtos .... 


16 


379. Heouravay 


26 


436. a' Chonnachair . . 15 


380. Kilcheran 


26 


437. a'Vullan 


15 


381. Monikie (North) 


26 


438. Birka .... 


15 


382. nan Druimnean 


26 


439. Kirk .... 


15 


383. Olavat .... 


26 


440. nan Eun (Ness) 


15 


384. Funds .... 


26 


441. a' Bhainne 


14 


385. an Tuirc .... 


25 


442. Gown (North) . 


14 


386. Davan .... 


25 


443. Anna 


13 


387. Syre .... 


25 


444. Beag .... 


13 


388. Ceo-Glas . ... 


24 


445. Bran .... 


13 


389. Lindores . . . 


24 


446. Bruadale 


13 



STATISTICAL TABLES 



xliii 



TABLE V continued 



Loch. 


Volume 
in 
Million 
Cubic 
Feet. 


Loch. 


Volume 
in 
Million 
Cubic 
Feet. 


447. Drumlamford . 


13 


505. na Doire Daraich . . 7 


448. Hostigates 


13 


506. na Gealaich . . . 7 


449. Littlester 


13 


507. Shechernich . . . j 7 


450. Lochenbreck . 


13 


508. Spvnie . . . . ; 7 


451. nah-Ealaidh . 


13 


509. Wester .... 7 


452. Skaill .... 


13 


510. a'Buaille ... 6 


453. Auchenchapel . 


13 


511. an Dubh (Lochy) . . 6 


454. Bad & Chrotha 


12 


512. Dallas . . . -6 


455. Cuil Airidh a' Flod . 


12 


513. Hightae Mill . . . \ 6 


456. Derclach. 


12 


514. na Bi . . . 6 


457. Geal .... 


12 


515. na Garbh-Abhuinn . . 6 


458. Kirk Dam 


12 


516. nan Aiiscot . . . 6 


459. na Coinnich 


12 


517. Monk My re . . .1.6 


460. Tormasad 


12 


518. Loch on Eilean Subhainn . 6 


461. a' Chlachain (Lewis) 


11 


519. Bogton .... 5 


462. Burraland 


11 


520. Brouster .... 5 


463. Clickhimin 


11 


521. Brow .... 5 


464. Eldrig . . . . 11 


522. Isbister . . . . : 5 


465. Mama .... 


11 


523. Kinellan . . . 5 


466. na Beiste 


11 


524. Kirriereoch 


5 


467. na Stainge 


11 


525. Lure .... 


5 


468. nan Garbh Chkchain 


11 


526. nan Gabhar 


5 


469. Peerie .... 


11 


527. nan Hath . . . 5 


470. Aboyne .... 


10 


528. Pitlyul . . . . j 5 


471. Allan .... 


10 


529. Sabiston .... 


5 


472. Aslaich .... 


10 


530. Stormont 


5 


473. Black (Etive) (West) 


10 


531. an t-Seasgain . 


4 


474. Con (Tay) 


10 


532. Crann .... 


4 


475. Dochart .... 


10 


533. Duddingston . 


4 


476. Essan .... 


10 


534. Grass .... 


4 


477. Gamhna .... 


10 


535. Maol a' Choire . 


4 


478. nah-Eaglais . 


10 


536. Tutach .... 


4 


479. nan Geireann . 


10 


537. Blairs .... 


3 


480. Tarruiim an Eithir . 


10 


538. Cornish .... 


3 


481. AiriJh na Ceardaich . 


9 


539. Duartmore 


3 


482. an lasgaich 


9 


540. Magillie .... 


3 


483. Laide .... 


9 


541. na Garbh-Abhuinn Ard 


3 


484. Lochnaw 


9 


542. Scolv .... 


3 


485. Lundie (Clunie) 


9 


543. a'Chladaich . 


2 


486. Moraig .... 


9 


544. an Tairbeirt Stuadhaich . 


2 


487. Muck .... 9 


545. Black (Tay) . 


2 


488. Rae .... 9 


546. Brough .... 


2 


489. Sandy .... 9 
490. Flugarth ... 8 


547. Buidhe(Tay) . 
548. Choire ua Cloich 


2 
2 


491. Fvntalloch ... 8 


549. Dubh (Etive) . 


2 


492. Mine' ille Riabhaich . 8 


550. Dubh (Xess) . 


2 


493. na Craige ... 8 


551. na Creige Leithe 


2 


494. Skae . . . . ' 8 


552. Rainbow .... 


2 


495. White (Tay) ... 8 


553. Sior .... 


2 


496. a' Chaoruinn . . .7 


554. Tilt .... 


2 


497. Asta .... 7 


555. nan Losganan . 


1 


498. Bosqnoy ... 7 


556. Sand .... 


1 


499. Clubbi Shuns . . 7 


557. Uaine . . . . 07 


500. Collaster . . 7 


558. Dubh (Forth) . . . 0'6 


501. Cults .... 7 


559. Setter . . . . ! 0'6 


502. Dhomhnuill Bhig . . 7 


560. Dhu (Portsonachan) . . 0'5 


503. Fithie .... 7 


561. St Margaret's ... 0'4 


504. Moor Dam ... 7 


562. AlltnaMult . . . O'l 



xliv 



THE FRESH -WATER LOCHS OF SCOTLAND 



TABLE VI 

FRESH- WATER LOCHS OF SCOTLAND (SOUNDED BY THE LAKE SURVEY) 
SHOWING SUMMARY OF PHYSICAL RESULTS 









Volume 




Drainage Area. 


Basins. 


Number Number 
of ofSound- 
Lochs. ings. 


in 
Million 
Cubic 

TToof 


Area 
of Lochs 
in Square 
Miles. 




Total 
in Square 


Ratio to 
Area of 






j: eeu. 




Miles. 


Lochs. 


Forth . 


13 


3,825 


36,543 


17-02 


227-66 


13-38 


Tay .... 


59 


6,851 


151,353 


39-81 


1099-52 


27-62 


Inver, Roe, Kirkaig, Polly, 














Garvie . . . . 


21 


2,540 


20,355 


12-64 


150-44 


11-9 


Morar .... 3 


1,284 


82,686 


10-99 


65-63 


6-0 


Ewe .... 


14 


2,473 


44,530 


14-80 


185-51 


12-5 


Shiel, Ailort, nan Uamh . 


6 


1,191 


28,967 


8-58 


99-97 


11-65 


Conou .... 


16 


2,188 


29,850 


11-65 


366-33 


31-5 


Shin .... 


11 


1,564 


14,538 


12-11 


239-69 


19-8 


Naver, Borgie, Kinloch, 














Hope .... 


11 


1,409 


15,615 


11-06 


239-46 21-7 


Beauly .... 


13 841 


11,227 


576 


215-26 


37-4 


Lochy .... 


12 2,570 85,855 


19-88 


293-42 


14-8 


Ness .... 


33 4,385 


280,923 


34-25 


689-14 20-1 


Brora, Helmsdale . 


11 700 


2,756 


6-68 


202-89 30-4 


Wick, Wester, Heilen, 










Dunnet, Thurso, Forss i 9 681 


1,319 


4-82 


168-25 34-9 


Laxford, Scourie, Badcall, 










Duartmore . 


10 994 6,679 


3-35 


59-20 177 


Broom, Gruinard 


11 1,141 


11,312 


7-10 111-50 15-7 


Gairloch, Torridon, Carron 


12 1,098 


4,921 


3-90 98-46 


25-2 


Alsh, Aline, Leven . 


10 


570 


2,067 


2-51 


85-25 


33-9 


Oban, Feochan, Seil, Mel- 














fort .... 


13 


855 


1,328 


1-66 


34-03 


20-5 


Bute, Eachaig . 


3 


372 


2,525 


2-07 


44-89 


21-7 


Doon, Girvan, Stinchar, 














Ryan, Galdenoch . 


13 


1,028 


1,935 


3-40 


75-16 


221 


Luce, Bladenoch, Cree 


15 


594 


427 


2-12 


35-43 


167 


Fleet, Dee 


13 954 


1,951 


4-02 


298-89 


74-4 


Urr, Nith, Annan . 


14 599 


652 


1-79 


2477 


13-7 


Tweed, Monikie, Lunan, 












Dee, Slains . 


16 879 


5,762 


4-24 


121-19 


28-6 


Spey .... 


13 


663 


2,053 


2-63 


350-50 


133-3 


Lossie, Findhorn, Nairn . 


10 


655 


5,179 


3-50 


42-41 12-1 


Lismore, Mull, Benbecula 


11 728 


5,475 


3-75 35-54! 9 '5 


Xorth Uist 


40 3,751 


3,026 


8-66 45-29 5'2 


Lewis .... 


30 2.896 


7,409 


9-64 151-98 15-8 


Orkney . 


14 '932 


2,321 


9-98 90-36 


9-1 


Shetland. 


31 1,707 


1,416 


5'36 51-89 


9-7 


Forth (Reservoirs) . 


20 1,065 


998 


3-07 43-69 14-2 


Etive .... 


21 2,619 48,451 


18-19 


307-55 


16-9 


Clyde .... 


7 2,487 93,331 


29-00 


314-40 


10-8 


Tay, Linnhe . 


3 106 79 


0-23 


3-51 


15-3 




562 59,195 


1,015,814 

f> .Q 


340-22 


6669-06 


19-6 






D y 

cubic 










miles 







INDEX TO THE DESCRIPTIONS AND MAPS OF 
THE SCOTTISH FRESH -WATER LOCHS 1 
SOUNDED BY THE LAKE SURVEY 

[The descriptions are bound in Vol. II., the maps in Yols. III., IV., V., and VI.] 



Abovne, \ 


'ol. 


II.- 


Par1 


:IL, 


P- 


148; 


Vol. 


V. 1 


Plat< 


sLII. 


Achall, 


55 


II. 


55 


II., 


P- 


39; 


55 


V. 


55 


XV. 


Achanalt, 


55 


II. 


55 


5 


P- 


267; 


55 


IV. 


55 


LVIII. 


Achilty, 


55 


II. 


55 


5 


P- 


275; 


55 


IV. 


55 


LXI. 


Achlaise, na h- 


55 


II. 


55 


5 


P- 


61; 


55 


III. 


55 


XVI. 


Achray, 


55 


II. 


55 


5 


P- 


5; 


55 


III. 


55 


V. 


Affric, 


55 


II. 


55 


5 


P- 


336; 


55 


IV. 


55 


LXXVIII. 


Ailsh, 


55 


II. 


55 


I-, 


P- 


301; 


55 


IV. 


55 


LXIX. 


Airidh na Cear- 






















daich, 


55 


II. 


55 


II., 


P- 


210; 


55 


VI. 


55 


LXXX. 


Airidh na Lie, 


55 


II. 


55 


II., 


P- 


211 ; 


55 


VI. 


55 


LXXXII. 


Airidh Sleibhe, 






















na h- 


55 


II. 


55 


II., 


P- 


32; 


55 


V. 


55 


XII. 


Aithness, 


55 


II. 


55 


II., 


P- 


238; 


55 


VI. 


55 


C. 


Allan, 


** 


II 




TT 


p 


165; 




V. 




LXIL 


A lit an Fhearna, 


55 


II. 


55 


II., 


P- 


11; 


55 


V. 


55 


II. 


Allt nah-Airbhe, 


55 


II. 


55 


II., 


P- 


34; 


55 


V. 


55 


XIII. 


Allt na Mult, 


55 


II. 


55 


II., 


P- 


278; 


55 


VI. 


55 


CXXIII. 


Alvie, 


55 


II. 


55 


II., 


P- 


157; 


55 


V. 


55 


LIX. 


Anna, 


55 


II. 


55 


II., 


P- 


64; 


55 


V. 


55 


XXIII. 


Aid, 


55 


II. 


55 


I-, 


P- 


15; 


55 


III. 


55 


IX. 


Arich-Lin, 


55 


II. 


55 


II., 


P- 


7; 


55 


V. 


55 


II. 


Arienas, 


55 


II. 


55 


II., 


P- 


66; 


55 


V. 


55 


XXV. 


Arkaig, 


55 


II. 


55 


I., 


P- 


359; 


55 


IV. 


55 


LXXXIV. 


Arklet, 


55 


II. 


55 


I., 


P- 


5; 


55 


III. 


55 


IV. 


Arthur, 


55 


II. 


55 


II., 


P- 


125; 


55 


V. 


55 


XLIII. 


Ashie, 


55 


II. 


55 


I, 


P- 


412; 


55 


IV. 


55 


XCII. 


Aslaich, 


55 


II. 


55 


t, 


P- 


401; 


55 


IV. 


it 


CI. 


Assynt, 


55 


II. 


55 


L, 


P- 


148; 


55 


III. 


55 


XXXV. 


Asta, 


55 


II. 


55 


II, 


P- 


244; 


55 


VI. 


55 


cm. 


Auchenchapel, 


55 


II. 


55 


L, 


P- 


122; 


55 


III. 


55 


XXXIII. 


Auchenreoch, 


55 


II. 


55 


II., 


P' 


124; 


55 


V. 


55 


XLIII. 


Auscot, nan 


55 


II. 


55 


II., 


P- 


178; 


55 


VI. 


55 


LXVIII. 


Avich, 


55 


II. 


55 


II., 


P- 


276; 


55 


VI. 


55 


CXXII. 



1 The spelling of the names of the lochs is uniform with that used in the 6-inch 
Ordnance Survey maps. 

xlv 



xlvi 



THE FRESH- WATER LOCHS OF SCOTLAND 



Awe (Etive Vol. II. Part II., p. 270 ; Vol. VI. Plates CXXII. and 

basin), CXXIII. 

Awe (Inver 



basin), 



II. 



I., p. 152 ; III. Plate XXXVI. 



Ba (Mull), 





II. 


55 


II, 


P- 


175; 


v. 





LXVI. 


Ba (Tay basin), 


55 


II. 


55 


I, 


P- 


62; 


HI. 


? , 


XVI. 


Bad a ? Chrotha, 


5, 


II. 


?9 


H, 


p. 


57; 


5, V. 


5, 


XVIII. 


Bad a' Ghaill, 


55 


II. 


55 


I, 


P' 


17; 


HI- 


55 


XLL 


Bad an Sgalaig, 


55 


II. 


5, 


II, 


P- 


53; 


v. 


55 


XVIII 


Baddanloch, 





II. 


,5 


II, 




10; 


v. 


55 


II. 


Baile sC Gho- 




















bhainn, 


5, 


II. 


55 


H, 


P- 


171; 


v. 


5, 


LXV. 


Balgavies, 


55 


II. 


,, 


H, 


p. 


144; 


55 V. 





LI. 


Beag, 


5* 


II. 


,, 


I, 


P- 


394; 


iv. 




XCIX. 


Beannach (Gruin- 




















ard basin), 


5, 


II. 


,5 


H, 


P- 


44; 


v. 


55 


XVII. 


Beannach (In- 




















ver basin), 


55 


II. 


,, 


I, 


P- 


153; 


III. 


5, 


XXXVI. 


Beannachan, 


55 


II. 


5, 


I, 


P- 


273; 


iv. 




LVIII. 


Beinn sC Mhea- 




















dhoin, 


,, 


II. 


,, 


I, 


P- 


338; 


iv. 





LXXIX. 


Beinne Baine, na 


,5 


II. 


,, 


I, 


P- 


340; 


iv. 





LXXXII. 


Beiste, na 


55 


II. 





H, 


P- 


46; 


v. 





XVII. 


Beithe, na 


55 


II. 


5, 


H, 


P- 


279; 


., VI. 





CXXXI. 


Benachally, 


55 


II. 





I, 


P- 


121; 


III. 





XXXIII. 


Benisval, 


55 


II. 





H, 


P- 


218; 


VI. 


55 


LXXXIX 


Beoraid, 


5, 


II. 


,5 


I, 


P- 


206; 


III. 


55 


XLIV. 


Bhac, 





II. 


5 


I, 


P- 


94; 


III. 


55 


XXVIII. 


Bhaid Daraich, a"* 





II. 


55 


II, 


P- 


30; 


v. 


? , 


XL 


Bhaid - Luach- 




















raich, sC 


5, 


II. 


,, 


I, 


P- 


228; 


III. 


,, 


L. 


Bhaillidh, a' 


55 


II. 


,, 


II, 


P- 


68; 


v. 


55 


XXVI. 


Bhainne, sC 


55 


II. 


55 


I, 


P- 


391; 


iv. 


55 


XCVL 


Bharpa, sC 




II. 


55 


H, 


P. 


200; 


VI. 




LXXI. 


Bhealaich, sC 




















(Alsh basin), 


5, 


II. 


55 


H, 


P- 


63; 


v. 


5, 


XXIV. 


Bhealaich, sC 




















(Gairloch 




















basin), 





II. 


55 


H, 


P- 


54; 


v. 


55 


XIX. 


Bhealaich, a' 




















(Naver basin), 


55 


II. 


55 


I. 


P- 


312; 


iv. 





LXXIII. 


Bhradain, 


55 


II. 


5, 


II. 


P- 


156; 


v. 


^ 


LVIII. 


Bhraoin, a" 


55 


II. 





II. 


P- 


38; 


v. 


?i 


XIV. 


Bhuird, a" 


55 


II. 





II. 


P- 


186; 


5, VI. 


,, 


LXX. 


Bi, na 


55 


II. 





II. 


P- 


275; 


VI. 


n 


CXXVI. 


Birka, 


55 


II. 


55 


H, 


P- 


236; 


VI. 


55 


XCVIII. 


Black (Etive 




















basin), 


,5 


II. 


5, 


IL, 


P- 


279; 


VI. 


55 


CXXX. 



INDEX TO THE DESCRIPTIONS AND MAPS xlvii 



Black (Ryan 
























basin), 


Vol. 


II. 


Part 


II. 


, 


P- 


100; 


Vol. 


V. 


Plate 


XXXVIII. 


Black (Tay 
























basin), 


55 


II. 


55 


I. 


5 


P- 


109; 


55 


III. 


55 


XXX. 


Blairs, 


55 


II. 


55 


II. 


5 


p. 


166; 


55 


V. 


55 


LXII. 


Boardhouse, 


55 


II. 


55 


II. 


5 


P- 


227; 


55 


VI. 


55 


XCIII. 


Bodavat. 


55 


II. 


55 


II. 


5 


P- 


219: 


55 


VI. 


55 


LXXXIX. 


Bogton, 





II. 


55 


II. 


5 




94; 


55 


V. 


55 


XXXVI. 


Borralan, 


55 


II. 


55 


I. 


, 


P- 


160; 


55 


III. 


55 


XXXVI. 


Bosquov, 


55 


II. 


55 


II. 


5 


P- 


225; 


55 


VI. 


55 


XC. 


Bradan, 


55 


II. 


55 


II. 





P- 


97; 


55 


V. 


55 


XXXVII. 


Braigh H orris - 
























dale, 


55 


II. 


55 


II. 


5 


P- 


56; 


55 


V. 


55 


XVIII. 


Bran. 


55 


II. 


55 


L 


5 




410; 


55 


IV. 


55 


XCI. 


Breac, nam 


55 


II. 


55 


II. 


5 


P- 


29: 


55 


V. 


55 


X. 


Breac Dearga, 
























nam 


55 


II. 


55 


L 


5 


P- 


399; 


55 


IV. 


55 


XCI. 


Breaclaich, 


55 


II. 


55 


I. 


5 


P- 


90; 


55 


III. 


55 


XXVII. 


Broom, 


55 


II. 


55 


I. 


5 


P- 


89; 


55 


III. 


55 


XXVII. 


Brora, 


55 


II. 


55 


II. 


5 


P- 


1; 


55 


V. 


55 


I. 


Brough, 


55 


II. 


55 


II. 


5 




245; 


55 


VI. 


55 


xcv. 


Brouster, 





II. 


55 


II. 


5 


P- 


240; 


55 


VI. 


55 


CI. 


Brow, 


M 


II. 


55 


II. 


5 




244; 


55 


VI. 


55 


CIV. 


Bruadale. 


55 


II. 


55 


II. 


5 


P- 


212; 


55 


VI. 


55 


LXXXIII. 


Buaille, a" 


55 


II. 


55 


II. 





P- 


200; 


55 


VI. 


55 


LXX. 


Buidhe (Fleet 
























basin), 


55 


II. 


55 


I. 





P- 


304; 


55 


IV. 


55 


LXX. 


Buidhe (Taj- 
























Basin), 


55 


II. 


55 


I. 


5 


p. 


60; 


55 


III. 


55 


XVI. 


Builg, 


55 


II. 


55 


II. 


5 


P. 


159; 


55 


V. 


55 


LXI. 


Bunacharan, 


55 


II. 


55 


I. 


5 


P- 


348: 


55 


IV. 


55 


LXXXII. 


Burga, 


55 


II. 


55 


II. 


5 


P- 


241; 


55 


VI. 


55 


CI. 


Burnt island, 


55 


II. 


55 


II. 


5 


P- 


255 : 


55 


VI. 


55 


CXVI. 


Burraland, 


55 


II. 


55 


II. 





P- 


234; 


55 


VI. 


55 


XCVIL 


Butterstone, 


55 


II. 


55 


I. 


5 


n. 


102: 


55 


III. 


55 


XXIX. 


Calavie, 


55 


II. 


55 


I. 


5 


p. 


344: 


55 


IV. 


55 


LXXXII. 


Calder, 


55 


II. 


55 


II. 


5 


P- 


21: 


55 


V. 


55 


VII. 


Callater, 


55 


II. 


55 


II. 


5 




146: 


55 


V. 


55 


LII. 


Cam, 


55 


II. 


' 55 


L 


5 


P- 


161: 


55 


III. 


55 


XXXVIII. 


Caol na Doire, 


55 


II. 


55 


II. 


5 




154; 


55 


V. 


55 


LVI. 


Caravat, 


55 


II. 


55 


II. 


5 


P- 


196; 


55 


VI. 


55 


LXXV. 


Carlingwark, 


55 


II. 


55 


II. 





p. 


120: 


55 


V. 


55 


XLIV. 


Castle (Annan 
























basin), 


55 


II. 


55 


II. 


5 


p. 


131 ; 


55 


V. 


55 


XLVII. 


Castle (Blade- 
























noch basin), 


55 


II. 


55 


II. 


5 


P. 


107: 


55 


V. 


55 


XLI. 


Castle Semple, 


55 


II. 


55 


II. 


5 


p. 


267; 


55 


VI. 


55 


cxxxm. 


Ceithir- 
























Eileana, na 


55 


II. 


55 


II. 





P- 


199; 


55 


VI. 


55 


LXXV. 



xlviii THE FRESH- WATER LOCHS OF SCOTLAND 



Ceo-Glas, Vol 


. II. 


Part IL, 


P- 


167; 


Vol 


. V. 


Plate LXIV. 


Chaluim, 


55 


II. 


55 


I., 


P- 


321; 


,, 


IV. 


55 


LXXVL 


Chaoruinn, a"* 


55 


II. 





II., 


P- 


80; 


55 


V. 


55 


XXXI. 


Chlachain, a' 






















(Lewis), 


55 


II. 


,, 


II., 


P- 


211 ; 


55 


VI. 


55 


LXXXI. 


Chlachain, a' 






















(Nairn basin), 


55 


II. 





II., 


p. 


169; 


55 


V. 


55 


LXIV. 


Chladaich, sC 


55 


II. 


55 


II., 


P- 


195; 


5, 


VI. 





LXXV. 


Chlair, sC (Helms- 






















dale basin), 


55 


II. 


5, 


II., 


P- 


9; 


55 


V. 


55 


II. 


Choire, sC 


,5 


II. 


,, 


L, 


P- 


410; 


55 


IV. 


5, 


CV. 


Choire na 






















Cloich, 


55 


II. 


,5 


IL, 


P- 


278; 


55 


VI. 


55 


CXXIIL 


Chon (Forth 






















basin), 


55 


II. 


55 


I-, 


P- 


13; 


55 


III. 


55 


VIII. 


Chonnachair, a' 


55 


II. 


,5 


IL, 


p. 


200; 


55 


VI. 


55 


LXXVII. 


Chroisg, a" 


55 


II. 


55 


I., 


P- 


263; 


55 


IV. 


,5 


LVII. 


Chuilinn, a 1 






















(Conon basin), 


55 


II. 


55 


L, 


P- 


267; 


55 


IV. 


,5 


LVIII. 


Clair (Ewe 






















basin), 


,5 


II. 


55 


I-, 


P- 


222; 


55 


III. 


,, 


XLIX. 


Claise Fearna, na 


55 


IL 


55 


IL, 


P- 


28; 





V. 


,, 


X. 


Clickhimin, 


55 


II. 


55 


IL, 


p. 


234; 


55 


VI. 


55 


XCV. 


Cliff, 


55 


II. 


5, 


IL, 


P- 


246; 


55 


VI. 


5, 


CVI. 


Clings, 


55 


II. 


55 


IL, 


P- 


239; 


55 


VI. 


55 


C. 


Clousta, 


55 


II. 


,, 


IL, 


P- 


238; 


55 


VI. 


55 


C. 


Clubbi Shuns, 


55 


II. 


55 


IL, 


p. 


235; 


55 


VI. 


55 


XCVIII. 


Clunie (Ness 






















basin), 


55 


II. 





I-, 


p. 


395; 


55 


IV. 


55 


XCIX, 


Clunie (Tay 






















basin), 


55 


II. 


55 


I., 


P- 


103; 


55 


III. 


55 


XXX. 


Coinnich, na 


55 


II. 


5, 


IL, 


P- 


199; 


55 


VI. 


55 


LXXV. 


Coir" an Fhearna, 


55 


II. 


,5 


I., 


P- 


313; 


55 


IV. 


55 


LXXIII. 


Coire nam 






















Meann, 


55 


II. 





II. , 


P- 


5; 





V. 


55 


II. 


Collaster 


55 


II. 


55 


IL, 


P- 


242; 


55 


VI. 


55 


C. 


Con (Tay basin), 


55 


II. 


55 


I., 


P- 


95; 


55 


III. 


55 


XXVIII. 


Cornish, 


55 


II. 


5, 


IL, 


P- 


96; 


55 


V. 


55 


XXXVII. 


Coulin (Ewe 






















basin), 


55 


II. 


55 


I., 


P- 


223; 


55 


III. 


55 


XLIX. 


Craggie, 


55 


IL 


,, 


L, 


P- 


302; 


55 


IV. 


55 


LXIX. 


Craige, na 


55 


II. 


,, 


I., 


P- 


86; 


55 


III. 


55 


XXVI. 


Craiglush, 


55 


II. 


5, 


I>5 


P- 


100; 


55 


III. 


55 


XXIX. 


Crann, 


55 


II. 


55 


I., 


P- 


263; 


55 


IV. 


55 


LVII. 


Craobhaig, na 


55 


IL 


55 


IL, 


P- 


217; 


55 


VI. 


55 


LXXXIX. 


Creagach, 


55 


II. 


55 


I, 


P- 


319; 


55 


IV. 


55 


LXXV. 


Creige Duibhe, na 


55 


II. 


55 


L, 


P- 


256; 


55 


IV. 


55 


LVI. 


Creige Leithe, na 


55 


II. 


55 


IL, 


p. 


193; 


55 


VI. 


55 


LXXV. 


Crocach, 


55 


II. 


55 


I, 


P- 


156; 


55 


III. 


55 


XXXVII. 


Cro Criosdaig, 


55 


II. 


55 


IL, 


P- 


218; 


55 


VI. 


55 


LXXXIX. 



INDEX TO THE DESCRIPTIONS AND MAPS 



xlix 



Crogavat. ^ 


i 


L II. 


Part 


II., 


P- 


194 


5 


Vol. 


VI. 


Plate 


LXXVI. 


Cronibie Den, 


5, 


II. 


55 


II., 


P- 


142 


5 


55 


V. 


55 


L. 


Crunachan, 





IL 


55 


II., 


P- 


154 


1 


55 


V. 


55 


LVL 


Cuaich, n a 


,, 


II. 


55 


II, 


P- 


155 


5 


55 


V. 


55 


LVIL 


Cuil Airidh a" 
























Flod, 


5, 


II. 


55 


II., 


P- 


210 


5 


55 


VI. 


5, 


LXXX. 


Cuil na Sithe, 





II. 


55 


L, 


P- 


316 


5 


55 


IV. 


55 


LXXIV. 


Cuinne, nan 


55 


IL 


55 


II., 


P- 


8 


5 


55 


V. 


55 


II. 


Cults, 


55 


II. 


55 


II., 


P- 


104 


1 


55 


V. 


55 


XXXIX. 


Daimh (Tav 
























basin). 


n 


II. 


55 


L, 


P- 


92 


5 


55 


III. 


55 


XXVII. 


Daimh, an 
























(Shin basin), 


5, 


II. 


55 


L, 


P- 


302 





55 


IV. 


55 


LXIX. 


Dallas, 


,5 


II. 


55 




P- 


165 


5 


5, 


V. 


,5 


LXIL 


Damn (Tom- 
























don basin), 


55 


II. 


55 


IL, 


P- 


58 


* 


55 


V. 


55 


XX. 


Da van. 


,5 


II. 


55 


II., 


P- 


148 


; 


55 


V. 


55 


LIV. 


Deaspoirt, nan 


55 


II. 


55 


II., 


P- 


210 


; 


,5 


VI. 


55 


LXXX. 


Dee, 


55 


II. 


55 


IL, 


P- 


114 





55 


V. 


?5 


XLIV. 


Dee (Expan- 
























sions of River), 


55 


II. 





II., 


P- 


119 


; 





V. 


55 


XLV. 


Deighe fo Dheas, 


- 






















na 


55 


II. 


55 


IL, 


P- 


179 


; 


5, 


VI. 


5? 


LXVIIL 


Deoravat, 


55 


II. 


55 


IL, 


P- 


186 


5 


' 55 


VI. 


55 


LXX. 


Derclach, 


,5 


II. 


55 


II, 


P- 


93 


; 


5, 


V. 


55 


XXXV. 


Derculich, 


5, 


IL 


55 


1-5 


P- 


83 


; 


55 


III. 


55 


XXVI. 


Dhomhnuill 
























Bhig, 


55 


II. 


55 


IL, 


P- 


210 


; 


55 


V. 


55 


LXXX. 


Dhti (Portso- 
























nachan Hill), 


55 


II. 


55 


IL, 


P- 


278 


; 


55 


VI. 


55 


CXXIII. 


Dhugaill (Tor- 
























ridon basin), 


55 


II. 


55 


IL, 


P- 


58 





55 


V. 


55 


XX. 


Dhughaill (Car- 
























ron basin), 


55 


II. 


55 


IL, 


P- 


60 





55 


V. 





XXII. 


Dibadale, 




II 




II 


P 


t? 17 


. 




VI. 




LXXXVII. 


Dilate, 


55 


II. 


55 




P- 


247 


; 


55 


IV. 


55 


LIV. 


Dithreibh. an 


55 


II. 


55 


L, 


P- 


322 


i 


55 


IV. 


55 


LXXVI. 


Dot-hard, 


55 


II. 


55 


IL, 


P- 


274 





5, 


VI. 


55 


CXXVII. 


Dochart. 


55 


II. 


55 


L, 


P- 


74 


* 





III. 


5, 


XX. 


Doine. 


5, 


II. 


55 


L, 


P- 


9 


" 




III. 


55 


VII. 


Doire Daraich, 
























na 




II 




I 




1.V4- 


. 




III. 




XXXVI. 


Doire nain Mart. 


,, 


II. 


55 


IL, 


P- 


66 


i 


,5 


V. 


55 
5, 


XXV. 


Doon. 


55 


IL 


55 


IL, 


P- 


91 


J 


55 


V. 


55 


XXXIV. 


Dornal, 





II. 


55 


II., 


P- 


109 




55 


V. 


55 


XLIL 


Drainc, an 


5, 


II. 


5, 


L, 


P- 


231 


* 


55 


III. 


55 


L. 


Droighinn. an 


55 


II. 


,5 


IL, 


P- 


277 


; 


55 


VI. 


55 


CXXIII. 


Droma, 


55 


II. 


55 


IL, 


P- 


38 


* 


55 


V. 


55 


XV. 


Druimnean. nan 


55 


II. 


55 


IL, 


P- 


80 





55 


V. 


55 


XXXI. 
























d 



THE FRESH-WATER LOCHS OF SCOTLAND 



Druim Suarda- 






















lain, 


Vol. 


II. 


Part 


I 


P' 


153 1 


M 


TIT 


Plate 


XXXVI. 


Drumellie, 





II. 




L, 


P- 


105; 


55 


III. 




XXX. 


Drumlamford, 


,5 


II. 





II, 


P- 


98; 


55 


V. 


55 


XXXVII. 


Drummond, 


55 


II. 





L, 


P- 


119; 


55 


III. 


55 


XXXII. 


Drunkie, 


55 


II. 





L, 


P- 


8; 


55 


III. 


5, 


V. 


Duartmore, 


55 


II. 





II, 


P- 


35; 


55 


V. 


M 


XIII. 


Dubh (Etive 






















basin), 


55 


II. 


M 


II, 


P- 


273; 


55 


VI. 


5, 


CXXVI. 


Dubh (Forth 






















basin), 


55 


II. 





L, 


P- 


14; 


55 


III. 


5, 


VIII. 


Dubh (Gair- 






















loch basin), 


55 


II. 





II, 


P- 


52; 


55 


V. 





XVIII. 


Dubh (Gruin- 






















ard basin), 


55 


II. 


,, 


II, 


P- 


43; 


55 


V. 


55 


XVII. 


Dubh (nan 






















Uamh basin), 


55 


II. 


55 


L, 


P- 


253; 


55 


IV. 


55 


LVI 


Dubh (Ness 






















basin), 


55 


II. 


55 


I, 


]). 


401; 


55 


IV. 


55 


XCI. 


Dubh, an 






















(Lochy basin), 


55 


II. 


55 


L, 


P- 


371; 


55 


IV. 


55 


LXXXIX. 


Dubh -Mor, 


55 


II. 


55 


II, 


P- 


79; 


55 


V. 


5, 


XXXI. 


Duddingston, 


55 


II. 


55 


II, 


P- 


252; 


55 


VI. 


55 


ex. 


Duiri, an (Spey 






















basin), 





II. 


55 


II, 


P- 


155; 


55 


V. 


55 


LVII. 


Duin, an (N. 






















Uist), 





II. 


55 


II, 


P 


191; 


55 


VI. 


55 


LXXIII. 


Duna, an 





II. 


55 


II, 


P- 


212; 


55 


VI. 


55 


LXXXIV. 


Dungeon, 


55 


II. 


55 


II., 


P- 


117; 


55 


V. 


55 


XLIV. 


Dun na Seil- 






















cheig, 


55 


II. 


55 


II, 


P- 


167; 


55 


V. 


55 


LXIV. 


Eaglais, na h- 


55 


II. 


55 


II., 


P- 


261; 


5, 


VI. 


5, 


CXX. 


Ealaidh, na h- 


55 


II. 


55 


II, 


P- 


26; 


,5 


V. 


5, 


VIII. 


Earba, na h- 


55 


II. 


55 


I, 


P- 


362; 





IV. 





LXXXV. 


Earn, 


55 


II. 


55 


L, 


P- 


75; 


55 


III. 





XXII. 


Eck, 


55 


II. 


55 


II, 


P- 


87; 


55 


V. 


,, 


XXXIII. 


Ederline, 




II. 




II. 


n. 


275 ; 




VI 




CXXII. 


Edgelaw, 


5, 


II. 


55 


IL, 


P- 


252; 


55 


VI. 




CVIII. 


Eela, 





II. 


55 


II, 


P- 


237; 





VI. 


,, 


XCIX. 


Eigheach 




II. 




I, 


P- 


67; 


M 


III. 




XVIII. 


Eilde Mor, 





II. 


5, 


II, 


P- 


70; 


55 


V. 





XXVII. 


Eileach Mhic 






















'ille Riabhaich 


, ,, 


II. 


,, 


II, 


P- 


45: 


55 


V. 


55 


XVII. 


Eilein,an(Gair- 






















loch basin), 





II. 


,5 


II, 


!> 


49; 


55 


V. 


55 


XVIII. 


Eilein, an (Spey 






















basin), 





II. 


5, 


II, 


P- 


158; 





V. 


5, 


LX. 


Eilt, 





II. 


,5 


I, 


l>- 


249; 





IV. 





LV. 



INDEX TO THE DESCRIPTIONS AND MAPS 



li 



Eion Mhic Ala- 



Eldrig, 


T \ /i 
99 


II. 


99 


II. 


9 


I" 
P- 


104; 


99 


V. 


99 


XXXIX. 


Ericht, 


99 


II. 


99 


L 


9 


P- 


54; 


99 


III. 


99 


XII. to XIV. 


Essan, 


99 


II. 


99 


I. 


'9 


P- 


90; 


99 


III. 


99 


XXVII. 


Eun, nan (NY^ 
























basin), 


99 


II. 


99 


I. 


9 


P- 


406; 


99 


IV. 


99 


cm. 


Eun, nan (North 
























Uist), 


99 


II. 


99 


II. 


"> 


P 


187; 


99 


VI. 


99 


LXXI. 


Eun, nan (Tay 
























basin), 


99 


II. 


99 


L 


9 


P- 


99; 


99 


III. 


99 


XXVIII. 


Eye, 


99 


II. 


99 


I. 


9 


P- 


281; 


99 


IV. 


99 


LXIV. 


Fad, 


99 


II. 


99 


II. 


9 


P- 


84; 


99 


V. 


99 


XXXII. 


Fada (Ewe 
























basin), 


99 


II. 


,, 


L 


9 


P- 


219; 


99 


III. 


99 


XLVIII. 


Fada (Gruinard 
























basin), 


99 


II. 


99 


II. 


9 


P- 


46; 


99 


V. 


99 


XVII. 


Fada (North 
























Uist), 


99 


II. 


99 


II. 


J 


P- 


190; 


99 


VI. 


99 


LXXII. 


Fadagoa, 
Fannich, 


99 

5 


II. 
II. 


99 
99 


II. 
I. 


9 
9 


P- 
P- 


209; 
268; 


99 
99 


V. 
IV. 


99 
99 


LXXX. 
LIX. 


Faoileag, nani 


99 


II. 


99 


II. 


9 


P- 


208; 


99 


VI. 


99 


LXXX. 


Fender, 


99 


II. 


99 


I. 


, 


P- 


115; 


99 


III. 


J9 


XXXI. 


Fiart, 


99 


II. 


99 


II. 


9 


P- 


172; 


99 


V. 


99 


LXV. 


Fingask, 


99 


II. 


99 


I. 


, 


P- 


107; 


99 


III. 


99 


XXX. 


Finlas, 


99 


II. 


99 


II. 


9 


P- 


93; 


99 


V. 


99 


XXXV. 


Fiodhaig, 


99 


II. 


99 


I. 


9 


P- 


299; 


99 


IV. 


99 


LXVIII. 


Fionn (Gruin- 
























ard basin), 


99 


II. 


99 


II. 


) 


P- 


42; 


99 


V. 


99 


XVII. 


Fionn (Kirkaig 
























basin), 


99 


II. 


99 


I. 


9 


P- 


166; 


99 


III. 


99 


XXXVIII. 


Fithie, 


99 


II. 


99 


II. 


? 


P- 


143; 


99 


V. 


99 


LI. 


Bitty, 


99 


II. 


99 


II. 


9 


P- 


256; 


99 


VI. 


99 


CXVI. 


Fleet, 


99 


II. 


99 


II. 







113; 


99 


V. 


99 


XLVI. 


Flugarth, 


99 


II. 


99 


II. 


9 


P- 


236; 


99 


VI. 


99 


XCIX. 


Forfar, 




II 




I 




P 


124; 




III. 




XXXIII. 


Preuchie, 


99 
99 


II. 


99 


I. 





P- 


113; 


99 


III. 


99 
99 


XXXI. 


Prisa, 


99 


II. 


99 


II. 


9 


P- 


174; 


99 


V. 


99 


LXVII. 


Fyntalloch, 


99 


II. 


99 


II. 


9 


P- 


106; 


99 


V. 


" 


XL. 


Gabhar, nan 


99 


II. 


99 


L 




P- 


373; 


99 


IV. 


99 


XC. 


Gainmheich, 


99 


II. 


99 


I. 





P- 


168; 


99 


III. 


99 


XXXIX. 


Gamhna, 


99 


II. 


99 


II. 


> 


P- 


157; 


99 


V. 


99 


LX. 


Garbh-Abhuinn, 
























na 


99 


II. 


99 


II. 


9 


P- 


189; 


99 


VI. 


99 


LXXII. 


Garbh-Abhuinn 
























Ard, na 


99 


II. 


99 


II. 


> 


P- 


189; 


99 


VI. 


99 


LXXII. 


Garbhaig, 


99 


II. 


99 


I. 


> 


P- 


221; 


99 


III. 


99 


XLVI. 



Hi 



THE FRESH-WATER LOCHS OF SCOTLAND 



Garbh-Clachan, 
nan Vol. 
Garry (Ness 
basin), 


II. Part II, 
II. I, 


P- 
P- 


193; Vol. VI. Plate LXXV. 
389; IV. XCV. 


Garry (Tay 




















basin), 


55 


II. 


,, 


I., 


P- 


57 ; 


III. 





XV. 


Gartmorn, 


55 


II. 


,, 


II., 


P- 


254; 


VI. 


,5 


CXIV. 


Garve, 


55 


II. 


55 


I., 


P- 


277; 


IV. 


55 


LXI. 


Gead, an 


55 


II. 


55 


I-, 


P- 


345; 


IV. 




LXXXII. 


Geal, 


55 


II. 


55 


II., 


P- 


266; 


VI. 


n 


CXXIV. 


Gealaich, na 


n 


II. 


55 


IL, 


P- 


278; 


VI. 


n 


CXXIII. 


Geireann, nan 


,5 


II. 


55 


II, 


P- 


190; 


VI. 


55 


LXXIL 


Geireann, nan 




















(Mill), 





II. 


55 


II, 


P- 


192; 


VI. 


11 


LXXIV. 


Gelly, 


w 


II. 


55 




P- 


256; 


VI. 




CXVI. 


Gh i uragarst idh , 


55 


II. 


55 


L', 


P- 


227; 


III. 


,, 


XLVII. 


Ghlinne - Dor - 




















cha, a' 


55 


II. 


55 


II 5 


P- 


193; 


VI. 


,, 


LXXVI. 


Ghobhainn, a' 


55 


II. 


55 


II, 


P- 


55; 


v. 




XIX. 


Ghriama, a 1 


5, 


IL 


55 


I., 


P- 


298; 


iv. 


,5 


LXVIL 


Ghuilbinn, 


,5 


II. 


55 


I., 


P- 


368; 


iv. 


5, 


LXXXVIL 


Giorra, 


55 


II. 


55 


I-, 


P- 


94; 


III. 


11 


XXVII. 


Girlsta, 


55 


II. 


55 


II, 


P- 


234; 


VI. 


11 


XCVI. 


Gladhouse, 


55 


II. 


55 


II, 


P- 


251; 


VI. 


,5 


CVII. 


Glass, 


55 


II. 


55 


I., 


P- 


279; 


iv. 


55 


LXII. 


Gleann a 1 Bhear- 




















raidh, 


,5 


II. 


55 


II, 


P- 


73; 


v. 


55 


XXVIII. 


Gorm Loch 




















Mor, 


55 


II. 


55 


I., 


P- 


300; 


iv. 


55 


LXIX. 


Gown, 


55 


II. 


55 


I., 


P- 


265; 


iv. 


55 


LVIL 


Grass, 


55 


II. 


55 


II, 


P- 


240; 


VI. 


55 


CI. 


Grennoch, 


55 


II. 


5, 


II, 


P- 


115; 


v. 


55 


XLIV. 


Grunavat, 


55 


II. 


,, 


IL, 


P- 


214; 


VI. 


55 


LXXXVL 


Gryfe, 


5, 


II. 





II, 


P- 


267; 


VI. 


55 


CXXXIV. 


Harelaw, 


55 


II. 


,, 


II, 


P- 


253; 


VI. 


55 


CXIL 


Harperleas, 


55 


II. 


,, 


IL, 


P- 


257; 


VI. 


n 


CXVI. 


Harperrig, 


55 


II. 





II, 


P- 


253; 


VI. 


,5 


CXI. 


Harray, 


55 


IL 


,, 


II, 


P- 


225; 


VI. 


5, 


XC. 


Harrow, 


55 


IL 


,, 


IL, 


P- 


118; 


v. 


,5 


XLIV. 


Heilen, 


55 


II. 





II, 


P- 


17; 


v. 


55 


V. 


Hempriggs, 


55 


II. 





II, 


P- 


15; 


v. 


55 


III. 


Heouravay, 


55 


II. 


,5 


II, 


P- 


178; 


VI. 


55 


LXVIII. 


Hermidale, 


55 


II. 


5, 


II, 




179; 


VI. 


55 


LXVIII. 


Hightae Mill, 


55 


II. 


55 


II, 


P- 


132; 


v. 


55 


XLVII. 


Hoglinns, 
Hoil, 


55 
55 


II. 
II. 


55 
55 


II, 
I., 


P- 
P- 


229; 
114; 


VI. 

III. 


55 
55 


XCIV. 
XXXI. 


Holl, 


55 


II. 


55 


IL, 


P- 


257; 


VI. 


55 


CXVII. 


Hope, 


55 


II. 


5, 


I-, 


P- 


324; 


,, iv. 


55 


LXXVIL 


Hosta 


,, 


II. 


,5 


II, 




192; 


VI. 


55 


LXXIII. 



INDEX TO THE DESCRIPTIONS AND MAPS 



liii 



Hostigates, 


Vol. 


II. 


Part 


II., 


P- 


239; 


Vol. 


VI. 


Plate 


c. 


Howie, 





II. 


99 


II., 


P- 


126: 


55 


V. 


99 


XLVL 


Huna. 




II. 


99 


II., 


P- 


lcS7: 


55 


VI. 


99 


LXXI. 


H under, 


55 


II. 





II., 


P- 


201; 


55 


VI. 


55 


LXXVII. 


Hundland. 


55 


II. 


99 


II., 


P- 


228; 


55 


VI. 


55 


XCIII. 


[asgaich, an 


99 


II. 


99 


II.. 


P- 


198; 


55 


VI. 


55 


LXXV. 


Ic Colla. 


99 


II. 


99 


II., 


P- 


198; 


55 


VI. 


55 


LXXV. 


Inbhir. 


99 


II. 


99 


11-9 


P- 


70; 


55 


V. 


55 


XXVI. 


lush. 


99 


II. 


99 


II., 


P- 


156; 


55 


V. 


55 


LEX. 


Isbister. 


99 


II. 


99 


II., 


P- 


226; 


55 


VI. 


55 


XCI. 


lubhair, 


95 


II. 


99 


L, 


P- 


75: 


55 


III. 


55 


XX. 


Katrine, 


55 


II. 


99 


L, 


P- 


1; 


55 


III. 


55 


IV. 


Kemp, 


55 


II. 


99 


L, 


P- 


405; 


55 


IV. 


55 


XCI. 


Ken, 


55 


II. 


99 


II., 


P- 


119; 


55 


V. 


55 


XLV. 


Kennard, 


55 


II. 


99 


L, 


P- 


87; 


5, 


III. 


55 


XXVI. 


Kernsarv. 




II. 




I 




^26 ' 




Ill 




XLVII. 


Kilbirnie, 


55 
59 


II. 


99 
99 


II., 


P- 


266; 





VI. 


55 


CXXXII. 


Kilcheran, 


99 


II. 


99 


II., 


P- 


172: 





V. 


55 


LXV. 


Kilchoan, 


99 


II. 


99 


II., 


P- 


81; 


55 


V. 


55 


XXX. 


Kilconquhar, 


.. 


II. 


99 


II., 


P- 


257: 


55 


VI. 


55 


CXVIII. 


Killin, 


99 


II. 


99 


L, 


P- 


406; 


55 


IV. 


55 


cm. 


Kindar, 


99 


II. 


99 


II., 


P- 


127; 


59 


V. 


55 


XLVL 


Kinellan, 


95 


II. 


99 


L, 


P- 


278; 


55 


IV. 


55 


LXI. 


Kinghorn, 


55 


II. 


99 


II., 


P- 


256 : 


55 


VI. 


55 


CXVI. 


Kinord, 


55 


II. 


99 


II., 


P- 


148; 


5, 


V. 


55 


LTV. 


Kirbister, 


55 


II. 


99 


II., 


P- 


226; 





VI. 


55 


XCII. 


Kirk, 


55 


II. 


99 


II-, 


P- 


131; 


,5 


V. 


55 


XLVII. 


Kirk Dam, 


55 


II. 


99 


H., 


P- 


84; 


55 


V. 


55 


XXXII. 


Kirriereoch, 


55 


II. 


99 


II., 


P- 


109; 





V. 


55 


XLII. 


Knock ie, 


55 


II. 


99 


L, 


P- 


404; 


55 


IV. 


55 


XCI. 


I^again, an 






















(Shin basin). 


55 


II. 


99 


L, 


P- 


304; 


55 


IV. 


55 


LXX. 


I^aggan (Lochy 






















basin), 


55 


II. 


99 


L, 


P- 


364; 


55 


IV. 


55 


LXXXV. 


Laghair, an 


55 


II. 


99 


I., 


P- 


338; 


55 


IV. 


55 


LXXIX. 


Laide. 


55 


II. 


99 


L, 


P- 


402; 


55 


IV. 


55 


XCII. 


Laidon, 


55 


II. 


99 


I., 


P- 


63: 


55 


III. 


55 


XVII. 


Laig Aird, an 


55 


II. 


99 


II-, 


P- 


30; 


55 


V. 


55 


XL 


Lairige, na 


55 


II. 


99 


L, 


P- 


91; 





III. 


99 


XXVII. 


Langavat 






















(Benbecula), 


59 


II. 


99 


II., 


P- 


180; 


,5 


VI. 


99 


LXVIII. 


Langavat 






















(Lewis), 


99 


II. 


55 


II., 


P- 


213; 


59 


VI. 


99 


LXXXV. 


I^ann, nan 


99 


II. 


55 


I., 


P- 


405; 


95 


IV. 


99 


XCI. 


Laoghal, 


99 


II. 


55 


I-, 


P- 


316; 


99 


IV. 


99 


LXXV. 


Leitir Easaich, 


99 


II. 


55 




P- 


151; 


99 


III. 


95 


XXXV. 



liv 



THE FRESH- WATER LOCHS OF SCOTLAND 



Leitreach, na Vol. 


II. Part II., 


P- 


63; 


Vol, 


V. Plate XXIII. 


I ,eodsay, 


55 


II. 


55 


II., 


P- 


193; 


55 


VI. 


55 


LXXV. 


Leoid, an 


55 


II. 


55 


II., 


P- 


277; 


55 


VI. 


55 


CXXIII. 


Leum a 1 Chla- 






















mhain, 


55 


II. 


55 


II., 


P- 


6; 


55 


V. 


55 


II. 


Leven, 


55 


II. 


55 


L, 


P- 


18; 


55 


III. 


55 


XI. 


Liath, 


>J 


II. 


55 


I., 


P- 


398; 


55 


IV. 


55 


CI. 


Lindores, 


J 


II. 


55 


II., 


P- 


260; 


55 


VI. 


55 


CXIX. 


Linlithgow, 


55 


II. 


55 


II., 


P- 


254; 


9) 


VI. 


55 


CXIII. 


Lintrathen, 


55 


II. 


55 


I-, 


P- 


123; 


55 


III. 


55 


XXXIII. 


Littlester, 


55 


II. 


55 


II., 


P- 


246; 


55 


VI. 


55 


cv. 


Loch, 


55 


II. 


55 


I., 


P- 


97; 


55 


III. 


55 


XXVIII. 


Lochaber, 


55 


II. 


55 


II., 


P- 


127; 


55 


VI. 


55 


XLVI. 


Lochenbreck, 


55 


II. 


55 


II., 


P- 


116; 


55 


V. 


55 


XLIV. 


Lochindorb, 


55 


II. 


55 


II, 


P- 


164; 


55 


V. 


55 


LXIII. 


Lochinvar, 


55 


II. 


55 


II, 


P- 


118; 


55 


V. 


55 


XLIV. 


Lochnaw, 


55 


II. 


55 


II, 


P- 


101; 


55 


V. 


55 


XXXIX. 


Lochrutton, 


55 


II. 


55 


II, 


P- 


127; 


55 


V. 


55 


XLVI. 


Lochy, 


55 


II. 


55 


I., 


P- 


356; 


55 


IV. 


55 


LXXXIII. 


Lomond, 


55 


II. 


55 


II, 


P- 


262; 


55 


VI. 


55 


CXXIV. and 






















cxxv. 


Long, 


55 


II. 


55 


I., 


P- 


111; 


55 


III. 


55 


XXX. 


Losgainn Mor, 






















an 


55 


II. 


55 


II, 


P- 


81; 


55 


V. 


55 


XXXI. 


Losganan, nan 


55 


II. 


55 


I., 


P- 


407; 


55 


IV. 


55 


cm. 


Lowes (Tay 






















basin), 


5? 


II. 


55 


I., 


P- 


101; 


55 


III. 


55 


XXIX. 


Lowes (Tweed 






















basin), 


55 


II. 


55 


II, 


P- 


136; 


55 


V. 


55 


XLIX. 


Loyne, 


55 


II. 


55 


L, 


P- 


396; 


55 


IV. 


55 


C. 


Lubnaig, 


55 


II. 


55 


L, 


P- 


11; 


55 


III. 


55 


VI. 


Luichart, 


55 


II. 


55 


I., 


P- 


271; 


55 


IV. 


55 


LX. 


Lundie (by 






















Clunie), 


5? 


II. 


55 


L, 


P- 


396; 


55 


IV. 


55 


XCIX. 


Lundie (by 






















Garry), 


55 


II. 


55 


L, 


P- 


391; 


55 


IV. 


55 


XCVI. 


Lungard, 


5? 


II. 


55 


L, 


P- 


341; 


55 


IV. 


55 


LXXXII. 


Lunn da-Bhra, 


5? 


II. 


55 


L, 


P- 


372; 


55 


IV. 


55 


XC. 


Lure, 


55 


II. 


55 


II, 


P- 


96; 


55 


V. 


55 


XXXMI. 


Lurgain, 


55 


II. 


55 


L, 


P- 


172; 


55 


III. 


55 


XL. 


Lyon, 


55 


II. 


55 


I, 


P- 


72; 


55 


III. 


55 


XXI. 


Maberry, 


55 


II. 


55 


II, 


P- 


106; 


55 


V. 


55 


XL. 


Magillie, 


55 


II. 


55 


II, 


P- 


103; 


55 


V. 


55 


XXXIX. 


Mama, 


55 


II. 


55 


L, 


P- 


256; 


55 


IV. 


55 


LVI. 


Maol a' Choire, 


55 


II. 


55 


L, 


P- 


152; 


55 


III. 


55 


XXXVI. 


Maree, 


55 


II. 


55 


L, 


P- 


211; 


55 


III. 


55 


XLVI. and 






















XLVII. 


Martnaham, 


55 


II. 


55 


II, 


P- 


94; 


55 


V. 


55 


XXXVI. 


Meide, na 


55 


II. 


55 


I., 


P- 


309; 


55 


IV. 


55 


LXXI. 



INDEX TO THE DESCRIPTIONS AND MAPS 



Meiklie, 


Vol. 


II. 1 


Part 


I 




400; ^ 


l"Tl 


TV 1 


3 lat( 


jCII. 


Menteith. 




II. 


55 


I., 


P- 


16; 


55 


III. 


55 


X. 


Merkland, 





II. 


55 


L, 


P- 


297: 


11 


IV. 


55 


LXVII. 


Mhic" Ille Ria- 






















bhaich, 


n 


II. 


5, 


L, 


P- 


229; 


55 


III. 


5, 


L. 


Mhiotailt. a 1 


11 


II. 





I., 


P- 


165; 





III. 


,5 


XXXVIII. 


Mhor (Ness 






















basin), 


11 


II. 


11 


I, 


P- 


408; 


55 


IV. 





CIV. 


Mhuilinn, a" 


11 


II. 


11 


I5 


P- 


347 : 


55 


IV. 


,5 


LXXXII. 


Micrdale. 


11 


II. 


11 


I 5 


P- 


303; 


55 


IV. 


55 


LXX. 


Mill. 


11 


II. 


11 


II., 


P- 


130; 


11 


V. 


55 


XLVII. 


Milton, 


55 


II. 


11 


II., 


P- 


125; 


11 


V. 


11 


XLIII. 


Mochrum, 





II. 


11 


II., 


P- 


108; 


11 


V. 


11 


XLI. 


Moine, na 





II. 


11 


II., 


P- 


11; 


11 


V. 


11 


II. 


Moine Buige, na 


,5 


II. 


55 


II., 


P- 


45; 


11 


V. 


11 


XVII. 


Monar, 


55 


II. 


,5 




P- 


346; 


11 


IV. 


11 


LXXXL 


Monikie. 


55 


II. 


55 


II." 


P- 


141; 


11 


V. 


11 


L. 


Monk Mvre. 


55 


II. 


55 


L, 


P- 


110; 


11 


III. 


11 


XXX. 


Monzievaird, 


55 


II. 


55 


I-, 


P- 


119; 


11 


III. 


11 


XXXII. 


Moor Dam, 


11 


II. 


55 


ii., 


P- 


255 ; 


11 


VI. 


11 


cxv. 


Moracha, na 


11 


II. 


11 


IL, 


P- 


187; 


11 


VI. 





LXXI. 


Moraig, 




II 




T 


p 


97: 




HI. 




XXVIII. 


Morar, 


55 

5*5 


II. 


11 




P- 


197; 


55 


III. 


,5 


XLIII. 


More (Laxford 






















basin), 


55 


II. 


11 


IL, 


P- 


24; 


55 


V. 





VIII. 


More (Thurso 






















basin), 


55 


II. 


11 


II., 


P- 


19; 


55 


V. 





VI. 


More Barvas, 


55 


II. 


11 


II., 


P- 


212; 


55 


VI. 





LXXXII. 


Morie, 


55 


II. 





I", 


P- 


280; 


55 


IV. 


55 


LXIII. 


Morlich, 





II. 





II-, 


P- 


158; 


55 


V. 





LXL 


Morsgail, 


,5 


II. 





IL, 


P- 


215; 


55 


V. 


,5 


LXXXVII. 


Moy, 





II. 


,5 


IL, 


P- 


164; 


55 


V. 


55 


LXII. 


Muck, 


,, 


II. 


55 


IL, 


P- 


94; 


55 


V. 


55 


XXXVI. 


Muckle Lunga, 





II. 





IL, 


P- 


236; 


5, 


VI. 


55 


XCVIII. 


Muckle Water, 


11 


II. 


.. 


IL, 


P- 


228: 





VI. 


5, 


XCI. 


Muick, 


11 


II. 


11 


IL, 


P- 


14(i: 





V. 


55 


LIII. 


Mullardoch. 


11 


II. 


11 


L, 


P- 


342 ; 





IV. 


55 


LXXX. 


Nant, 


55 


II. 


11 


II., 


P- 


27cS: 




VI. 





CXXIII. 


Naver, 


55 


II. 







P- 


311; 





IV. 





LXXII. 


Nell. 


11 


II. 


11 


IL,' 


P- 


75: 




V. 





XXIX. 


Ness, 




II 




I 


i) 


381; 




IV. 




XCI. and XCII. 


North-house. 


11 


II. 


11 


IL, 


P- 


241 : 





VI. 


55 
55 


C. 


Nostarie, an 


11 


II. 


11 


I-, 


P- 


207: 





III. 


55 


XLV. 


Oban sC Chlach- 






















ain, 


.. 


II. 


11 


IL, 


P- 


192; 


w 


VI. 





LXXV. 


Oban nam 






















Fiadh, 




II 




IT 




196; 




VI. 




LXXV. 


Obisary, 


55 


II. 


11 


IL, 


P- 


194; 





VI. 





LXXVI. 



Ivi 



THE FRESH-WATER LOCHS OF SCOTLAND 



Ochiltree, 

Oich, 

Oidhche, na h- 

Olavat, 

Ordie, 

Ossian, 

Owskeich, 

Pattack, 

Peerie, 

Peppermill, 

Phearsain, a' 

Phitiulais, 

Pitlyal, 

Portmore, 

Poulary, 

Punds, 

Quoich, 

Rae, 

Rainbow, 

Rannoch, 

Raoinavat, 

Raonasgail, 

Rath, nan, 

Ree, 

Rescobie, 

Roer, 

Rosebery, 

Ruathair, an 

Ruthven, 

Sabiston, 
St John's, 
St Margaret's, 
St Mary's, 
Salach Uidhre, 

na 

Sand, 
Sandy, 
Scadavay, 
Scamadale, 
Scarmclate, 
Scaslavat, 
Scoly, 
Sealbhag, 
Seasgain, an t- 
Seil, 
Seilich, an t- 



II. ] 


Part 


II, 


p. 107 ; 1 


Vol. 


V. 1 


3 late 


XL. 


II. 


99 


I., 


p. 392 : 





IV. 


95 


XCVII. 


II. 


99 


II, 


p. 51; 





V. 


55 


XIX. 


II. 


99 


II, 


p. 180 ; 





VI. 


55 


LXIX. 


II. 


99 


1-5 


p. 85; 





III. 


55 


XXVI. 


II. 


99 


L, 


p. 366 ; 


55 


IV. 


55 


LXXXVI. 


II. 


99 


I-, 


p. 174 ; 





III. 


99 


XLI. 


II. 


99 


L, 


p. 361 ; 


fj 


IV. 


55 


LXXXIX. 


II. 


99 


II, 


p. 229; 





VI. 


55 


XCI. 


II. 


99 


II-, 


p. 255 ; 





VI. 


55 


cxv. 


II. 


99 


II, 


p. 80; 


95 


V. 


55 


XXXI. 


II. 


99 


II, 


p. 159; 





V. 


55 


LX. 


II. 


99 


L, 


p. 112; 


n 


III. 


55 


XXX. 


II. 


99 


II, 


p. 252 ; 





VI. 


55 


CIX. 


II. 


55 


1-5 


p. 389 ; 


99 


IV. 


55 


XCIV. 


II. 


55 


II, 


p. 237 ; 


99 


VI. 


55 


XCVII. 


II. 


55 


L, 


p. 388 ; 


99 


IV. 


55 


xcm. 


II. 


55 


I., 


p. 106 ; 


99 


III. 


99 


XXX. 


II. 


59 


II, 


p. 278 ; 


99 


VI. 


99 


CXXIII. 


II. 


99 


L, 


p. 68; 


99 


III. 


99 


XIX. 


II. 


99 


II, 


p. 213 ; 


99 


VI. 


99 


LXXXIV. 


II. 


99 


II, 


p. 216 , 


99 


VI. 


99 


LXXXVIII. 


II. 


99 


II, 


p. 279 ; 


99 


VI. 


99 


CXXXI. 


II. 


99 


II, 


p. 104; 


99 


VI. 


99 


CXXI. 


II. 


59 


II, 


p. 143; 


99 


V. 


99 


LI. 


II. 


99 


II, 


p. 235 ; 


95 


VI. 


99 


XCVIII. 


II. 


99 


II, 


p. 251 ; 


55 


VI. 


99 


CVIII. 


II. 


99 


II, 


p. 4; 


55 


V. 


99 


II. 


II. 


99 


L, 


p. 411 ; 


55 


IV. 


99 


cv. 


II. 


99 


II, 


p. 225 ; 


99 


VI. 


99 


XCI. 


II. 


99 


II, 


p. 18; 


99 


V. 


99 


V. 


II. 


99 


II, 


p. 252 ; 


99 


VI. 


99 


ex. 


II. 


99 


II, 


p. 137 ; 


99 


V. 


99 


XLIX. 


II. 


59 


II, 


p. 69; 


99 


V. 


95 


XXVI. 


II. 


99 


II, 


p. 150 ; 


99 


V. 


99 


LV. 


II. 


99 


II, 


p. 223 ; 


99 


VI. 


99 


xcv. 


II. 


99 


II., 


p. 188 ; 


99 


VI. 


99 


LXX. 


II 




IT 


p. 76; 




V 




XXIX. 


II. 


55 


II, 


p. 14; 


55 


V. 


99 


III. 


II. 


59 


II, 


p. 217; 


55 


VI. 


55 


LXXXVIII. 


II. 


55 


I., 


p. 84; 


55 


III. 


95 


XXVI. 


II. 


55 


L, 


p. 343 ; 


5J 


IV. 


,9 


LXXX. 


II. 


99 


II, 


p. 198 ; 


55 


VI. 


55 


LXXV. 


II. 


55 


II, 


p. 77; 


55 


V. 


55 


XXX. 


II. 


59 


II, 


p. 156; 


59 


V. 


55 


LVIII. 



INDEX TO THE DESCRIPTIONS AND MAPS 



Ivii 



Setter, 


Vol. 


II. 


Part 


II. 


'9 


P- 


245 ; 


Vol. 


VI. 


Plate 


xcv. 


Sgamhain, 


99 


II. 


95 


II. 





P- 


60; 


99 


V. 


99 


XXI. 


Sguod, 


99 


II. 


59 


I. 


9 


P- 


230; 


59 


III. 


99 


L. 


Sheallag, na 


99 


II. 


99 


II. 





P- 


40; 


99 


V. 


99 


XVI. 


Shechernich. 


99 


II. 


99 


I. 


9 


P- 


122 ; 


99 


III. 


99 


XXXIII. 


Shiel, 


99 


II. 


99 


I. 


9 


P- 


241; 


99 


IV. 


99 


LII, LIII. 


Shin. 


99 


II. 


99 


I. 


9 


P- 


293; 


,9 


IV. 


99 


LXV, LXVI. 


Shurrerv. 


99 


II. 


55 


II. 


9 


P- 


20; 


99 


V. 


55 


VII. 


Si or. 


99 


II. 


55 


II. 


, 


P- 


278; 


99 


VI. 


55 


CXXIX. 


Skae. 


99 


II. 


55 


II. 


, 


P- 


126; 


99 


V. 


55 


XLVI. 


Skaill, 


99 


II. 


59 


II. 


, 


P- 


228; 


99 


VI. 


55 


XCIV. 


Skealtar, 


99 


ii. 


99 


II. 


9 


P- 


189; 


99 


VI. 


55 


LXXII. 


Skebacleit, 


99 


n. 


99 


II. 


9 


P- 


206; 


99 


VI. 


55 


LXXVIII. 


Skeen (Annan 
























basin), 


99 


n. 


99 


II. 


9 


P- 


129; 


. 99 


V. 


59 


XLVII. 


Skene (Dee 
























basin. Aber- 












. 












deen ), 


99 


ii. 


99 


II. 


, 


P- 


149: 


99 


V. 


99 


LII. 


Skeirow, 


99 


n. 


99 


II. 


, 


P- 


115; 


99 


V. 


95 


XLIV. 


Skiach, 


99 


ii. 


99 


I. 


, 


P- 


88; 


99 


III. 


55 


XXM. 


Skinaskink, . 


99 


n. 


99 


I. 


J 


P- 


169; 


99 


III. 


55 


XXXIX. 


Slagain, an t- 


M 


n. 


99 


I. 


, 


P- 


230; 


99 


III. 


55 


L. 


Sloy. 


99 


ii. 


99 


II. 


9 


P- 


266; 


99 


VI. 


55 


CXXIV. 


Snarravoe, 


99 


ii. 


99 


II. 


9 


P- 


247: 


99 


VI. 


55 


cv. 


Soul seat, 


99 


n. 


99 


II. 





P- 


103; 


99 


V. 


55 


XXXIX. 


Spiggie, 


99 


ii. 


99 


II. 


9 


P- 


244: 


99 


VI. 


59 


CIV. 


Spynie, 


99 


ii. 


99 


II. 


9 


P- 


162; 


99 


V. 


99 


LV. 


Sreinge, na 


99 


n. 


99 


II. 





P- 


75 : 


99 


V. 


99 


XXVIII. 


Sron Sineur, 


99 


ii. 


99 


I. 


9 


P- 


66; 


99 


III. 


99 


XVIII. 


Staca. an 


* 99 


n. 


99 


I. 


* 


P- 


398; 


99 


IV. 


99 


CI. 


Stack. 


99 


n. 


99 


II. 


9 


P- 


27 : 


9, 


V. 


99 


IX. 


Stacsavat, 


99 


n. 


99 


II. 


9 


P- 


215; 


99 


VI. 


99 


LXXXVI. 


Stainge. na 


99 


ii. 


99 


I. 


9 


P- 


60; 


99 


III. 


99 


XVI. 


Stem 


99 


n. 


99 


II. 


9 


P- 


224: 


99 


VI. 


99 


xc. 


Stormont, 


99 


n. 


99 


I. 


9 


P- 


110; 


99 


III. 


99 


XXX. 


Strandavat. 


55 


ii. 


99 


II. 


9 


P- 


207; 


99 


VI. 


99 


LXXIX. 


Strom, 


55 


n. 


99 


II. 


, 


P- 


242 : 


99 


VI. 


99 


CII. 


Strom ore, an 


55 


ii. 


99 


II. 


* 


P- 


190 | 


99 


VI. 


99 


LXXII. 


Suai naval, 


59 


n. 


55 


IL, 


P- 


215; 


95 


VI. 


99 


LXXXM. 


Subhainn,Loch 
























on Eilean, 


99 


n. 


59 


I. 


9 


P- 


216; 


55 


III. 


99 


XLVII. 


Swannav. 


99 


ii. 


99 


II. 


9 


P- 


227: 


59 


VI. 


99 


XCIII. 


Syre. 


99 


ii. 


99 


I. 


9 


P- 


314; 


59 


IV. 


99 


LXXIV. 


Tachdaidh, an 


99 


ii. 


59 


I. 


9 


P. 


344; 


59 


IV. 


99 


LXXXII. 


Tairbeirt Stua- 
























dhaich, an 


99 


n. 


99 


II. 


9 


P- 


186; 


55 


VI. 


99 


LXX. 


Talla, 


99 


n. 


99 


II. 


9 




135; 


99 


V. 


99 


XLVIII. 


Tankerness, 


99 


ii. 


99 


II. 


, 


P- 


226: 


99 


VI. 


99 


XCII. 


Tarff', 


99 


n. 


99 


I. 


, 


P- 


402; 


99 


IV. 


99 


XCI. 
























e 



Iviii 



THE FRESH-WATER LOCHS OF SCOTLAND 



Tarruin an 
Eithir, V 


ol. 


II. I 


'art 


II 


P- 


200; ^ 


^ol 


VI F 


late 


LXX. 


Tay, 


55 


II. 


55 


L, 


P- 


80; 


55 


III. 


55 


XXIV. and 






















XXV. 


Tearnait, 


55 


II. 


55 


II., 


P- 


67; 


55 


V. 


55 


XXV. 


Thorn, 


55 


II. 


55 


IL, 


P- 


267; 


55 


VI. 


55 


CXXXIV. 


Threipmuir, 


55 


II. 


55 


IL, 


P- 


253; 


55 


VI. 


55 


CXII. 


Tilt, 


55 


II. 


55 


I., 


P- 


96; 


55 


III. 


55 


XXVIII. 


Tingwall, 


55 


II. 


55 


II 5 


P- 


243; 


55 


VI. 


55 


cm. 


Tollie, 


55 


II. 


55 


L, 


P- 


225; 


55 


III. 


55 


XLVII. 


Tomain, an 


55 


II. 


55 


II, 


P- 


193; 


55 


VI. 


55 


LXXVI. 


Tormasad, 


55 


II. 


55 


II, 


P- 


199; 


55 


VI. 


55 


LXX I. 


Tralaig, 


55 


II. 


55 


II, 


P- 


78; 


55 


V. 


55 


XXXI. 


Trealaval, 


55 


II. 


55 


II, 


P- 


208; 


55 


VI. 


55 


LXXX. 


Treig, 


55 


II. 


55 


1-5 


P- 


369; 


55 


IV. 


55 


LXXXVIIL 


Trool, 


55 


II. 


55 


II, 


P- 


110; 


55 


V. 


55 


XLIL 


Truid air Sgi- 






















thiche, 


55 


II. 


55 


II, 


P- 


8; 


55 


V. 


55 


II. 


Tuirc, an 


55 


II. 


55 


L, 


P- 


157; 


55 


III. 


55 


XXXVIL 


Tulla, 


55 


II. 


55 


II, 


P- 


274; 


55 


VI. 


55 


CXXVIII. 


Tummel, 


55 


II. 


55 


L, 


P- 


78; 


55 


III. 


55 


XXIII. 


Turret, 


55 


II. 


55 


L, 


P- 


117; 


55 


III. 


55 


XXXIL 


Tutach, 


55 


II. 


55 


IL, 


P- 


165; 


5, 


V. 


55 


LXII. 


Uaine, 


55 


II. 


55 


L, 


P- 


118; 


55 


III. 


55 


XXXIL 


Uanagan, 


55 


II. 


55 


L, 


p. 


394; 


55 


IV. 


55 


XCVIII. 


Urigill, 


55 


II. 


55 


L, 


P- 


160; 


55 


III. 


55 


XXXVI. 


Urr, 


55 


II. 


55 


II, 


P- 


124; 


55 


V. 


55 


XLIII. 


Urrahag, 


55 


II. 


55 


II, 


P- 


212; 


55 


VI. 


55 


LXXXIII. 


Ussie, 


55 


II. 


55 


1-5 


P- 


278; 


55 


IV. 


. 


LXI. 


Vaara, 


55 


II. 


55 


II, 


p. 


238; 


55 


VI. 


55 


C. 


Valtos, 


55 


II. 


55 


II, 


P- 


208; 


55 


VI. 


55 


LXXX. 


Vatandip, 


55 


II. 


55 


II, 


P- 


211; 


55 


VI. 


55 


LXXXI. 


Veiragvat, 


55 


II. 


55 


II, 




191; 


55 


VI. 


55 


LXXII. 


Vennachar, 


55 


II. 


55 


I, 


P- 


6; 


55 


III. 


55 


V. 


Veyatie, 


55 


II. 


55 




P- 


163; 


55 


III. 


55 


XXXVIII. 


Voil, 


55 


II. 


55 


I, 


P- 


9; 


55 


III. 


55 


VII. 


Vullan, a 


55 


II. 


55 


1-5 


P- 


399; 


55 


IV. 


55 


CL 


Watten, 


55 


II. 


55 


II, 


P- 


15; 


55 


V. 


55 


III. 


Wester, 


55 


II. 


55 


II, 


p. 


17; 


55 


V. 


55 


IV. 


Whinyeon, 


55 


II. 


55 


II, 


p. 


120; 


55 


V. 


55 


XLIV. 


White (Ryan 






















basin), 


55 


II. 


55 


II, 


}>. 


100; 


55 


V. 


55 


XXXVIII. 


White (Tay 






















basin), 


55 


II. 


55 


L. 


, p. 


108; 


55 


III. 


55 


XXX. 


White of Myr- 






















ton, 


55 


II. 


55 


IL. 


, }> 


105; 


55 


V. 


55 


XXXIX. 


Whitefield, 


55 


II. 


55 


IL. 


P' 


104; 


55 


V. 


55 


XXXIX. 


Woodhall, 


55 


II. 


5, 


II, 


p. 


116; 


55 


V. 


55 


XLIV. 



VOLUME II 



PART I 



LOCHS OF THE FORTH BASIN. 

WITHIN this basin the following lochs were sounded by Sir John Murray 
and the late Mr. Fred. P. Pullar, viz., Lochs Katrine, Arklet, Achray, 
Vennachar, Drunkie, Voil, Doine, Lubnaig, Chon, Dubh, Ard, 
Menteith, and Leven. The eight first-mentioned lochs belong to the 
catchment-basin of the river Teith, and have a special interest from 
being directly or indirectly connected with the excellent water-supply 
to the city of Glasgow.* Loch Arklet belongs to the catchment-basin 
of Loch Lomond, but the Corporation of Glasgow has power to divert 
its waters into the catchment-basin of Loch Katrine. 

Loch Katrine (see Plate IV.). Loch Katrine is one of the best 
known and most beautiful of the Scottish lochs. The celebrated 

* In the year 1855 the Corporation of Glasgow was empowered by Act of Parliament 
to raise Loch Katrine 4 feet above, and to draw it down 3 feet below, the previous 
summer level, thus giving a total available depth of 7 feet for the supply of water to 
the city, the quantity of water to be drawn from the loch being restricted to fifty 
million gallons in twenty-four hours. For the purpose of providing compensation water 
to the riparian owners on the river Teith, power was also given to raise Loch Vennachar 
5 feet 9 inches above its previous summer level, and to draw it down 6 feet, and 
also to raise Loch Drunkie 25 feet. An aqueduct was built from the southern shore of 
Loch Katrine to Glasgow, 8 feet wide and 8 feet high throughout, with a semicircular 
top, and having a fall towards Glasgow of 10 inches per mile. At first only a portion 
of the available fifty million gallons per day was conveyed to Glasgow, but by the 
end of 1881, the whole of the works necessary to complete the original design were 
finished. In the year 1884 it was found necessary to provide a larger quantity of water 
in order to keep pace with the growth of the city, and it was then found that the rough- 
ness of the rock sides of the aqueduct had a very retarding influence upon the velocity 
of the water, and that the aqueduct could not be made to discharge more than forty-two 
million gallons per day. Power was subsequently obtained from Parliament to build a 
second aqueduct, to raise Loch Katrine an additional 5 feet, and to convert Loch Arklet, 
which flows into Loch I omond, into a reservoir by raising it 25 feet in level. These 
works are now i i progress, and when completed are estimated to give a supply of 
seventy-five millions of gallons of water per day to the city of Glasgow. Should a still 
greater supply be necessary in the future, it is believed this can be obtained by connecting 
Loch Doine with Lch Katrine by a tunnel through the intervening hills, and by con- 
structing an embankment at the bottom of Loch Doine to raise the water-level 30 feet, 
and another at the bottom of Loch Voil to raise the water-level of that loch 10 feet, 
and if still more water were wanted, Loch Lubnaig could furnish it (see papers by James 
M. Gale, Esq., M. INST. c.B , in the Traits. InsL Engineers in Scotland, vols. vii., xii., 
xxvi.. and xxxviii .. and his Report on the proposed extension of the Glasgow Corporation 
Wat.-r \V,,rks. dated May 17. 1884). 

U 



2 BATHYMETRICAL SURVEY OF 

woodland scenery of the Trossachs and Ellen's isle are situated at its 
south-eastern end, while splendid moorland scenery prevails at the north- 
western end. It has a total length of about 8 miles, with a maximum 
width of almost exactly 1 mile between the mouths of Letter burn and 
Strone burn on the northern shore to a small bay on the opposite shore. 
The mean breadth, obtained by dividing the area of the loch by its 
length, is 0'6 mile, or 1056 yards, being 7J per cent, of the length. 

The waters of the loch cover an area of 3059 acres (or 4f square 
miles), and it drains an area about eight times greater, or about 24,900 




FIG. 1. LOCH KATRINE AND ELLEN'S ISLE. 

(Photograph by J. Valentine.) 

acres (nearly 37 \ square miles). * The total number of soundings taken 
in Loch Katrine was 775, an average of 163 per square mile, and the 
average depth of these was 142 J feet, the greatest depth observed being 
495 feet (82 J fathoms). f The positions of the majority of the soundings 
are shown on Plate IV. 

* When the waters of I.och Arklet are diverted into Loch Katrine this drainage area 
will, of course, be extended. 

f As long ago as September, 1812, and September, 1814, Mr. James Jardine, C.E., 
recorded observations on the depth and temperature of Loch Katrine (see Buchan, Proc. 
Roy. Soc. Edin., vol. vii. p. 791, 1872). The maximum depth recorded by him is 480 
feet (80 fathoms), whereas, as stated above, we found a depth of 495 feet. His tempera- 
ture observations are given in the table of serial temperatures, and discussed along with 
the recent observations. We believe that Mr. J. Y. Buchanan took soundings and tem- 
peratures in Loch Katrine some years ago, but, as far as we are aware, they were 
never published, and are therefoi'e not available for discussion (see also Art. " Lake " in 
Encycl. Bi-it., 9th edit.). 



THE FRESH-WATER LOCHS OF SCOTLAND. 



2 < 




FIG. 3. CROSS-SECTIOW OF 

LOCH KATRINE. THE 

BLACK PORTION SHOWS 
THE TRUE SLOPES; THE 
OUTLINE SHOWS THE 
SLOPES EXAGGERATED 

TEN TIMES. 



The bulk of water con- 
tained in the loch is esti- 
mated at 27,274,000,000 
cubic feet, or about one- 
fifth of a cubic mile, and 
the mean depth (suppos- 
ing the loch to be of 
uniform depth over its 
present area) at 199 feet 
(33 fathoms), the mean 
depth being over 40 per 
cent, of the maximum depth. The length of the 
loch is 85 times the maximum depth, and 211 
times the mean depth. 

The surface of the loch is, according to the 
Ordnance Survey maps, at an elevation of 364 
feet above sea-level, so that our survey shows 
that a considerable portion of the bottom of 
the loch (equal to about 645 acres, or over one 
square mile) lies below sea-level, the deepest part 
being 131 feet (or 22 fathoms) below the level 
of the sea. The area below the level of the 
sea is indicated by a red line on Plate IV. In 
this respect Loch Katrine differs from the other 
lochs referred to in this paper, for in none of them 
is the depth sufficiently great to bring any portion 
of their bottoms below the level of the sea. 

The soundings show that Loch Katrine prac- 
tically forms a single basin, not being divided, like 
Loch Lomond and Loch Lubnaig, for instance, 
into separate basins by any important ridges or 
rises on the bottom. The deepest part is in the 
centre of the loch, a long narrow depression, with 
depths exceeding 400 feet, extending for over 4 
miles from opposite Coilachra to opposite Ruinn 
Dubh-aird, with a maximum width of over a quar- 
ter of a mile ; this 400-f eet depression has an area 
of about 515 acres, or 17 per cent, of the entire 
superficial area of the loch. The deepest sounding 
(495 feet) is situated at the very eastern extremity 
of the 400-f eet depression. 

The 300-feet depression is over 5 miles in 
length, with a maximum breadth of one-third of a 
mile ; it extends from off Coilachra to near Ellen's 
isle. The area enclosed between the 300-feet and 



4 BATHYMETRICAL SURVEY OF 

400-feet contour-lines is about 415 acres, or 13 per cent, of the entire 
area of the loch. 

The 200-feet depression is 5J miles in length and half a mile in 
maximum breadth, extending from south of Ellen's isle to near Black 
island, where it is separated (by a sounding of 198 feet) from a small 
isolated area, lying between Coilachra and Black island, one-third of a 
mile in length by nearly one-eighth of a mile broad. The area between 
the 200- and 300-feet contours is about 510 acres, or 17 per cent, of the 
area of the loch. 

There are two 100-feet depressions, the principal one (6 miles in 
length) stretching from close to Ellen's isle to Black island, the other 




FIG. 4. LOCH ARKLET, LOOKING WEST. 

(Photograph by G. W. Wilson.) 



extending from Black island towards the point called Rudha nam 
Moine, with a total length of over half a mile. The area enclosed 
between the 100- and 200-feet contours is about 670 acres, or 22 per 
cent, of the area of the loch. 

The 50-feet line follows pretty closely the contour of the loch, from 
Rudha nam Moine into the eastern arms of the loch at the Trossachs, 
running outside of Black island, Ellen's isle, and the small islands near 
the shore all round, with a small isolated patch at the junction of the 
Trossachs arm with the arm leading to Achray Water; it encloses a 
small shallow, with a beacon on it, opposite the entrance of the Glasa- 
hoile. The area between the 50- and 100-feet contours is about 400 



THE FRESH- WATER LOCHS OF SCOTLAND. 5 

acres, or 13 per cent, of the area of the loch, while the area between the 
coast-line and the 50-feet contour is nearly 550 acres, or 18 per cent, 
of the area of the loch, so that 82 per cent, of the floor of the loch is 
covered by over 50 feet of water. 

Loch A r filet (see Plate IV.). Loch Arklet drains into Loch Lomond, 
but the corporation of the city of Glasgow have power, by the erection 
of a dam at its west end, to divert the waters into the catchment- 
basin of Loch Katrine, in order to increase the supply of water to the 
city. The surface of this little moorland loch is, according to the 
Ordnance Survey maps, 455 feet above sea-level. It has a total length 
of over a mile, and a maximum width near the east end of nearly half 
a mile. The mean breadth is about one-third of a mile, or 587 yards, 
being 33 per cent, of the length. Its waters cover an area of about 
210 acres (0'3 square mile), and it drains an area about sixteen times 
greater, or about 3400 acres (5J square miles). The number of sound- 
ings taken in Loch Arklet was 135, the average depth of these being 
21 feet, and the greatest depth observed being 67 feet (11 fathoms). 
The mass of water in the loch is estimated at 222,000,000 cubic feet, 
and the mean depth at 24 feet, or 36 per cent, of the maximum depth. 
The length of the. loch is 79 times the maximum depth, and 218 times 
the mean depth. 

The wide eastern portion of Loch Arklet is shallower than the 
narrower western portion. The 50-feet depression extends little more 
than halfway towards the eastern end of the loch, and is slightly under 
half a mile in length, the greatest depth (67 feet) being approximately 
near the centre of the depression, and nearer the western than the 
eastern end. The area of over 50 feet in depth is estimated at about 
19 acres, or 9 per cent, of the area of the loch, while the area between 
the 50-feet line and the shore is about 191 acres, or 91 per cent, of the 
entire superficial area. 

Two small islands appear on the chart in the shallower part of the 
loch towards the north-eastern end. 

Loch Achray (see Plate V.). This pretty little lake is situated at 
the entrance to the Trossachs, and immediately before the windows of 
the Trossachs Hotel. Loch Achray, the surface of which is, according 
to the Ordnance Survey maps, 276 feet above sea-level, has a total 
length of about 1J miles, with a maximum width of nearly one-third of 
a mile. The mean breadth is about a quarter of a mile, or 458 yards, 
being nearly 21 per cent, of the length. Its waters cover an area of 
about 205 acres (one-third of a square mile), and the area draining into 
it is twenty-two times greater, or about 4500 acres (7 square miles). 
The number of soundings taken in Loch Achray was 171, and the average 
depth of these was 36J feet, the maximum depth recorded being 97 



6 BATHYMETRICAL SURVEY OF 

feet (16 fathoms). The bulk of water contained in the loch is estimated 
at 321,000,000 cubic feet, and the mean depth at 36 feet (6 fathoms), 
or 37 per cent, of the maximum depth. The length of the loch is 68 
times the maximum depth, and 183 times the mean depth. 

The 50-feet depression is over two-thirds of a mile in extreme length, 
with a maximum width of about one-fifth of a mile, lying uniformly 
near the centre of the loch, and covers an area of about 64* acres, or 31 
per cent, of the superficies of the loch. Within this area there is a 
depression occupying about 32 acres where the depths exceed 90 feet, 
the greatest registered depth (97 feet) being recorded in two places 
approximately in the centre of the loch. At the west end of the loch, 




FIG. 5. LOCH ACHRAY, LOOKING WEST TOWARDS BEN VENUE. 

(Photograph by J. Valentine.) 

not far from the hotel pier, a detached sounding of 50 feet is recorded ; 
off the mouth of the Achray water there are some shallow patches, and 
a shallow in the centre of the loch towards the west end, on which there 
are 2 to 3 feet of water, is marked by a beacon. The area less than 50 
feet in depth is estimated at about 141 acres, or 69 per cent, of the total 
area of the loch. The eastern end of the loch is relatively shallow; at 
one place there is a depression with 27 feet surrounded by shallower 
water, and at another place there is what appears to be a submerged 
crannog covered by only 1 or 2 feet of water. 

Loch Vennachar (see Plate V.). Loch Vennachar, the surface of 



THE FRESH- WATER LOCHS OF SCOTLAND. 7 

which is, according to the Ordnance Survey maps, 270 feet above sea- 
level, has a total length of about 4 miles, with a maximum width of less 
than three-quarters of a mile. The mean breadth is about two-fifths 
of a mile, or 704 yards, being 10 per cent, of the length. Its waters 
cover an area of about 1030 acres (or over 1| square miles), and it drains 
an area nearly eighteen times greater, or about 18,300 acres (28J square 
miles). The total number of soundings taken in Loch Vennachar was 
423, an average of 263 per square mile, the average depth of these being 
41 feet, and the greatest depth observed being 111 feet (18 \ fathoms), 
so that it may be regarded as a relatively shallow loch. The bulk of 
water contained in the loch is estimated at 1,903,000,000 cubic feet, 
and the mean depth at 42J feet (7 fathoms), being 38 per cent, of the 
maximum depth. The length of the loch is 190 times the maximum 
depth, and 498 times the mean depth. 




FIG. 6. LOCH VENNACHAR, LOOKING SOUTH-WEST. 

(Photograph hi/ G. W. Wilton.) 

It will be observed from an examination of the map that the loch is 
deeper in the eastern than in the western portion, the western end being 
shallow and covered with weeds, so that one must proceed nearly a mile 
from the west end of the loch before encountering depths of 50 feet, 
and this is merely a small patch separated from the principal 50-feet 
depression by a distance of nearly two-thirds of a mile. In August the 
water in the loch is at its lowest, and the weeds at the west end most 
abundant. The principal 50-feet depression is about 2 miles in length, 
with a mean breadth of about one-third of a mile and a maximum 
breadth of nearly half a mile. It includes two 100-feet depressions : the 
first one is very irregular in shape, situated approximately in the centre 
of the loch, and contains the greatest observed length (111 feet), which 
lies towards the northern shore; the second one occupies the central 
portion of the large 50-feet depression, the greatest depth observed 



8 BATHYMETRICAL SURVEY OF 

therein being 106 feet. Towards the eastern end of the large 50-feet 
depression is a small shallow patch in the centre of the loch opposite 
Portnellan, in which a depth of 36 feet was found. 

At the extreme eastern end are situated the sluices and weir, over 
which the compensation water passes into the river Teith; at some 
distance from the sluices the depth of water flowing over a weir is 
recorded twice a day. 

The area between the shore and the 50-feet contour is estimated at 
about 635 acres, or 62 per cent, of the entire superficial area of the loch, 
while the area between the 50- and 100-feet lines is estimated at about 
324 acres, or 31 per cent., and the area with depths over 100 feet is 
estimated at about 71 acres, or 7 per cent, of the area of the loch. 

Loch Drunkie (see Plate V.). This picturesque and irregular High- 
land loch is shut in on all sides by high hills, is difficult of access, and 
rarely visited. The surface of the loch, according to the Ordnance 
Survey maps, is 416 feet above the level of the sea, but it was raised 25 
feet in connection with the water-supply to the city of Glasgow, with 
the view of furnishing compensation water to the river Teith. The 
soundings shown on the map give the depth in the loch in April, 1899. 

Loch Drunkie is remarkable in many respects. It is the smallest 
of the five lochs in the Loch Katrine district, but deeper than the larger 
Loch Arklet situated at a similar high elevation, and quite as deep as 
the neighbouring Loch Achray situated at a lower elevation. In form 
it is peculiar, consisting of a quadrangular portion throwing out three 
arms of various sizes in different directions. The largest arm runs in a 
north-easterly direction, the extremity approaching within a quarter of 
a mile of the southern shores of Loch Vennachar; this arm contains 
the greatest depths observed in the loch, and near its extremity the 
Ordnance Survey map indicates a small island which was not seen. 
The second arm in point of size runs directly west, and contains a 
maximum depth of 80 feet. The smallest arm runs in a south-westerly 
direction, deepening gradually though irregularly from 6 feet at the 
extremity to 15 feet near the junction with the quadrangular body of 
the loch. 

The maximum length of the loch (between the extremities of the 
north-eastern and south-western arms) is over one mile ; from the 
extremity of the western arm to the opposite (eastern) shore of the loch 
is a little less. The maximum width of the quadrangular body of the 
loch is over a quarter of a mile. The mean breadth is 0*21 mile, being 
21 per cent, of the length. The waters of the loch cover an area of 
about 138 acres (0'22 square mile), and drain an area ten times greater, 
or over 1400 acres (2 '2 square miles). The number of soundings taken 
in Loch Drunkie was 155, the average depth of these being 38J feet, 
the greatest depth observed (exactly the same as in the case of Loch 



THE FRESH-WATER LOCHS OF SCOTLAND. 9 

Achray) being 97 feet (16 fathoms). The bulk of water contained in the 
loch is estimated at 217,000,000 cubic feet, and the mean depth at 36 
feet (or 6 fathoms), being 37 per cent, of the maximum depth. The 
length of the loch is 54 times the maximum depth, and 147 times the 
mean depth. 

There are two depressions with depths over 50 feet : one at the 
extremity of the western arm, about a quarter of a mile in length, 
and the other filling up the greater part of the body of the loch, and 
extending some distance up the north-eastern arm, being over one-third 
of a mile in length and about one-quarter of a mile in maximum width. 
The area over 50 feet in depth is estimated at 43 acres, or 31 per cent. 




FIG. 7. LOCHS VOIL AND DOINE, LOOKING WEST FROM EOB ROT S GRAVE, BALQUHIDDEB. 

(Photograph by J. Valentine.) 

of the total area of the loch, while the area between the shore and the 
50-feet contour is estimated at 95 acres, or 69 per cent, of the area of 
the loch. 



Lochs Voil and Doine. These two lochs, the surfaces of which, 
according to the Ordnance Survey maps, are situated at an elevation of 
414 feet above sea-level, formed at no very distant date a continuous 
loch, which has been divided into two portions principally by the 
deposition of material brought down Monachyle glen by the river ; this 
is supported by the fact that deep water extends close up to the dividing 
promontory of land on both sides. The former continuous loch must 



10 BATHYMETRICAL SURVEY OF 

have been over 4J miles in length. As the level of these two lochs is 
50 feet higher than the level of Loch Katrine, it has been suggested 
by Mr. Gale that the water-supply to the city of Glasgow could, if 
necessary, be increased by connecting these lochs to Loch Katrine by 
a conduit through the intervening hills. 

Loch Voil (see Plate VII.). Loch Voil has a total length of over 
3J miles, with a maximum width (near the western end) of about one- 
third of a mile. The mean breadth is about a quarter of a mile, or 
422 yards, being 7 per cent, of the length. The waters of Loch Voil 
cover an area of about 561 acres (0'88 square mile), and those of Loch 
Doine about 135 acres (0'21 square mile), or together over one square 
mile, while they drain an area thirty-five times greater, or about 24,600 
acres (nearly 38| square miles). 

The total number of soundings taken in Loch Voil is 279, the average 
depth of these being 39 J feet, and the greatest depth 98 feet (or 16 J 
fathoms). The bulk of water contained in the loch is estimated at 
1,000,000,000 cubic feet, and the mean depth at 41 feet (or nearly 
7 fathoms), being 42 per cent, of the maximum depth. The length of 
the loch is 189 times the maximum depth, and 451 times the mean 
depth. 

Loch Voil becomes narrower and shallower towards the eastern end ; 
one must proceed about a mile and a half (or over one-third of the length 
of the loch) from the eastern end before encountering depths of 50 feet, 
while deeper water is found towards the western end. The 50 -feet 
depression extends from quite close to the western end for a distance of 
2 miles towards the eastern end of the loch, with a maximum width 
of about a quarter of a mile. Towards the western end of the loch is a 
considerable area (over half a mile in length by a sixth of a mile in 
maximum breadth) having depths greater than 90 feet. In this all the 
deepest soundings are situated (the greatest depth, 98 feet, having been 
observed in two places). From this depression the bottom of the loch 
apparently rises very gradually towards the eastern end. 

The area over 50 feet in depth is estimated at about 230 acres, or 
41 per cent, of the entire area of the loch, while the area between the 
shore and the 50-feet line is estimated at about 331 acres, or 59 per 
cent, of the total extent of the loch. 

Loch Doine (see Plate VII.). Loch Doine has a total length of 
nearly one mile, with a maximum width of over a quarter of a mile ; 
the mean breadth is about 0'21 mile, or 370 yards, being 21 per cent, of 
the length. The total number of soundings taken in Loch Doine was 90, 
the average depth of these being 34 1 feet, the greatest depth being 
65 feet (11 fathoms). The bulk of water contained in the loch is 
estimated at 196,000,000 cubic feet, and the mean depth at 33 feet 
(5J fathoms). The length of the loch is 81 times the maximum depth, 
and 160 times the mean depth. 



THE FRESH-WATER LOCHS OF SCOTLAND. 11 

lii Loch Doine the deeper water occupies approximately the centre 
of the loch, the deepest soundings (65 feet) being found, however, nearer 
the eastern than the western end of the loch. The 50-feet depression 
covers over one-third of the area of the loch, being about three-quarters 
of a mile in length with a maximum width of over one-eighth of a mile. 
It seems doubtful whether this 50-feet depression is not really separated 
into a larger and smaller portion, for the narrow neck shown on the 
map is founded upon a single sounding of exactly 50 feet. The greatest 
depth, 65 feet, was observed in several spots situated towards the 
eastern end of the loch. The area with depths over 50 feet is estimated 
at 47 acres, or 35 per cent, of the entire area of the loch, while the area 
with depths less than 50 feet is estimated at 88 acres, or 65 per cent, 
of the area of the loch. 

Loch Lubnaig (see Plate VI.). The outflow from Lochs Doine and 
Voil passes by the river Balvag, 5 miles in length, into Loch Lubnaig, 
the surface of whose waters is, according to the Ordnance Survey maps, 
405 feet above sea-level, or 9 feet lower than that of the other two lochs. 
A consideration of the intervening ground indicates that in post-glacial 
times these three lochs formed one single sheet of water. 

Loch Lubnaig has a total length of nearly 4 miles, following ap- 
proximately a line drawn down the centre of the loch, with a maximum 
width of about two-fifths of a mile. The mean breadth is nearly a 
quarter of a mile, or 422 yards, being 6 per cent, of the length. Its 
waters cover an area of about 614 acres (or nearly 1 square mile), and it 
drains an area 36J times greater, or about 22,400 acres (nearly 35 square 
miles). The total number of soundings taken in Loch Lubnaig was 
394, the average depth of these being 20J feet, and the greatest depth 
observed 146 feet (24 J fathoms). The bulk of water contained in the 
loch is estimated at 1,144,000,000 cubic feet, and the mean depth at 
42^ feet (or 7 fathoms), being 29 per cent, of the maximum depth. 
The length of the loch is 145 times the maximum depth, and 493 times 
the mean depth. 

Loch Lubnaig differs from the other lochs in the neighbourhood in 
that it does not constitute a single basin. The bottom is apparently 
very irregular ; the contour lines of depth do not follow the contour of 
the loch, hollows and ridges alternate with each other, and in some 
places comparatively deep water is found close to the shore, while in 
other places shallow water extends a considerable distance from shore. 
The loch is also, comparatively speaking, very narrow and shallow con- 
sidering its size, nearly two-thirds of the area being under 50 feet in 
depth. The loch may be conveniently divided into two halves, defined 
by the central constriction in the outline of the loch at the entrance of 
the Ardchullarie burn, where the bottom shallows and separates the two 
principal deep depressions; the northern half trends in a north-west 



12 BATHYMETRICAL SURVEY OF 

and south-east direction, while the southern half trends almost directly 
north and south. 

There are two depressions in which the depth exceeds 100 feet, with 
an isolated sounding of 106 feet between them. The larger depression 
is contained in the southern half of the loch, and is over half a mile 
in length, with a maximum width of about one-sixth of a mile ; the 
greatest depth in this depression is 118 feet. The smaller but deeper 
depression is situated at the base of the northern half of the loch, 
occupying a central position, and is over a quarter of a mile in length, 
with a maximum width of about one-sixth of a mile. The deepest 
sounding in the loch (146 feet) is centrally placed in this depression, 




FIG. 8. LOCH LUBNAIG, LOOKING NORTH. 

(Photograph by G. W. Wilson.) 

lying north-westward of the point where the Ardchullarie burn enters 
the loch. The area of over 100 feet in depth is estimated at about 55 
acres, or 9 per cent, of the entire area of the loch 

There are three depressions in which the depth exceeds 50 feet. 
The largest is contained in the southern half of the loch, and is over 
1J miles in length, with a maximum width of over a quarter of a mile. 
The second in point of size is centrally placed, and is over half a mile 
in length, with a maximum width of over a quarter of a mile. The 
third and smallest (and also the shallowest, the deepest sounding in it 
being 62 feet) is situated near the northern end of the loch, and is little 
more than a quarter of a mile in length and about one-eighth of a mile 



THE FRESH- WATER LOCHS OF SCOTLAND. 13 

in greatest width. At the upper end of the loch, where the river 
Balvag enters, there is a long spit formed of detritus brought down by 
the river, and this end of the loch for a distance of three-quarters of a 
mile is very shallow, while at the lower end the 50-feet contour is 
found within 200 yards of the outlet. The area between the 50-feet 
and 100-feet contours is estimated at about 162 acres, or 26 per cent, of 
the total area of the loch, while the area with depths under 50 feet is 
estimated at about 397 acres, or 65 per cent, of the area of the loch. 

When the loch was visited on April 6, 1899, it appeared from marks 
on the shore that the water had lately been 4 feet 10 inches higher than 
at that time, and it has been known to have been 12 or 18 inches lower, 
so that the rise and fall is about 6 feet in all. On one occasion a disc 
was visible down to a depth of 17 ^ feet, and on another down to 20 J feet. 

On the western shore, between 1J and 1J miles from the southern 
end of the loch, there is a remarkable sandy spit, which stretches out 
towards the centre of the loch, the origin of which appears to us some- 
what puzzling (see the Geological Notes by Messrs. Peach and Home). 

Loch Chun (see Plate VIII.). There are two lochs in Perthshire bear- 
ing this name, the one a little loch in the parish of Blair Atholl. The 
Loch Chon now_ under consideration lies to the south of Loch Katrine, 
and trends in a north-west and south-east direction. It lies at a height 
of 296 feet above sea-level, and the river into which it flows expands, a 
little distance to the south-east, into the small loch, Lochan Dubh or 
Loch Dhu, the surface of which is 10 feet lower. Loch Chon is over 
In miles in length, and the greatest width is about one-third of a mile. 
The mean breadth, obtained by dividing the area of the loch by its 
length, is a quarter of a mile, being 15 per cent, of the length. Its 
waters cover an area of about 277 acres, or less than half a square mile, 
and it drains an area about 14i times greater, or nearly 4000 acres 
(nearly 6 J square miles) . The number of soundings taken in Loch Chon 
was 157, the greatest depth observed being 75 feet. The mass of water 
contained in the loch is estimated at 358,000,000 cubic feet, and the 
mean depth at over 29 feet, or 39 per cent, of the maximum depth. The 
length of the loch is 120 times the maximum depth, and 305 times the 
mean depth. 

Loch Chon is irregular in outline, and the contour-lines are also 
irregular. The deepest part of the loch (i.e. exceeding 50 feet) forms a 
long, narrow depression, situated approximately in the centre of the 
loch, but closer to the western than to the eastern shore, about seven- 
twelfths of a mile in length, with a maximum width of over one-sixth of 
a mile. The maximum depth, 75 feet, was found comparatively very 
close to the western shore, being in fact only about 130 yards distant; 
this gives a slope of almost 1 in 5, and a similar steep slope is indicated 
by the near approach to the shore of the contour-lines for a considerable 



14 



BATHYMETRICAL SURVEY OF 



distance along the western side of the loch. The slope from the eastern 
shore is, generally speaking, more gradual. The 25-feet depression is 
divided into two portions by the rising of the floor of the loch about a 
quarter of a mile from the southern end. The maximum depth in the 
smaller southern depression is 49 feet. The larger 25-feet depression, 
separated from the smaller one by an interval of about one-eighth of a 
mile, is over 1J miles in length, approaching close to the north-western 
end of the loch, with a maximum breadth of three-eighths of a mile. 
This larger depression is very irregular in outline, occupying nearly the 
full width of the loch towards the centre, while a short distance farther 
south there is a narrow constriction in the vicinity of the Heron islands. 




FIG. 9. LOCH CHON. 

(Photograph by G. W. Wilson.) 



The area of the bottom between the shore line and the 25-feet 
contour is about 119 acres, or 43 per cent, of the total area of the loch; 
that between the 25- and 50-feet contours is about 127 acres, or 46 per 
cent., and that deeper than 50 feet is about 32 acres, or 11 per cent. 

Lochan Dubh (see Plate VIII.). This little basin is one-fifth of a 
mile in length, and less than one-sixth of a mile in maximum width. 
Its waters cover an area of about 11 J acres, and it drains an area 
eighteen times greater, or about 205 acres. The mean breadth is less 
than one-tenth of a mile, or 45 per cent, of the length. Twenty-five 
soundings were taken in Lochan Dubh, the maximum depth observed 
being 41 feet. The cubic mass of water is estimated at 586,000 cubic 



THE FRESH-WATER LOCHS OF SCOTLAND. 



15 



feet, and the mean depth at nearly 21 feet, or 50 per cent, of the 
maximum depth. The length of the loch is 28 times the maximum 
depth, and 56 times the mean depth. 

Lochan Dubh is very simple in construction, shoaling on all sides 
down to the deepest part. As in Loch Chon the slope seems to be much 
steeper off the western than the eastern shore, a cast of 35 feet having 
been taken comparatively very close to the west side. The water 
shallows where the loch narrows a little above the outlet, a depth of 
3i feet being found where the bottom is covered with reeds. The area 
of the bottom between the shore and the 25-feet contour line is about 
7 acres, or 60 per cent, of the area of the loch, and that deeper than 
25 feet is nearly 5 acres, or 40 per cent. 




FIG. 10. LOCH ARD, WITH BEN LOMOND IN THE DISTANCE. 

(Photograph by J. Valentine.) 



Loch Ard (see Plate IX.). Loch Ard receives the outflow from 
Lochan Dubh and Loch Chon ; it trends in an east and west direction, 
sending out one prolongation to the south and another to the east. Its 
level is 105 feet above the sea. It is over three miles in extreme length, 
including the eastern prolongation, but the body of what may be called 
the loch proper is about 2 J miles in length : from the head of the loch 
to Helen's rock. The greatest width, measured from the extremity of 
the southern prolongation to the northern shore of the loch, is over one 
mile, the mean breadth being two-fifths of a mile. Its waters cover an 
area of over 600 acres (nearly one square mile), and it drains an area of 
more than ten times greater, or about 6250 acres (9J square miles). The 



16 BATHYMETRICAL SURVEY OF 

number of soundings taken in Loch Ard was 308, the maximum depth 
being 107 feet. Thus the deepest part of Loch Ard dips two feet below 
sea-level. The cubic mass of water contained in the loch is estimated at 
1,150,000,000 cubic feet, and the mean depth at nearly 44 feet, or 41 
per cent.- of the maximum depth. The length of the loch is 113 times 
the maximum depth, and 277 times the mean depth. 

Loch Ard proper forms a comparatively simple basin, shoaling from 
the shores down to the deepest part. The 100-feet depression occupies 
a central position, and is about three-quarters of a mile in length. The 
75-feet depression is over 1^ miles in length, while the principal 50-feet 
depression, over 1 \ miles in length, is separated by a very short interval 
from a small detached area in the north-western part of the loch at 
Kinlochard, in which the depth exceeds 50 feet. The 25-feet contour- 
line is very irregular, and there are four isolated patches in which the 
depth exceeds 25 feet : the largest one in the southern prolongation at 
Couligartan has a maximum depth of 39 feet ; a second small area occurs 
between the southern prolongation and the island of Eilean Gorm, in 
which the maximum depth is 35 feet ; the other two areas are situated 
in the eastern prolongation of the loch, the maximum depth in the 
eastmost depression near the outlet of the loch being 33 feet, and in 
the other 39 feet. The soundings taken between Duke Murdoch's 
castle and Briedach show that the bottom is very irregular : the first 
sounding gave a depth of 17 feet, followed by 44 feet, then 38 feet, then 
23 feet, then 31 feet, the bottom rising on approaching the elevation on 
which Briedach and a beacon are situated. 

The area of the bottom between the shore and the 25-feet contour- 
line is about 240 acres, or 40 per cent, of the area of the loch; that 
between the 25- and 50-feet contours is about 154 acres, or 25 per cent. ; 
that between the 50- and 75-feet contours is nearly 64 acres, or 11 per 
cent. ; that between the 75- and 100-feet contour-lines is about 78 acres, 
or 13 per cent. ; and that deeper than 100 feet is nearly 65 acres, or 
11 per cent. 

Lake of Menteith (see Plate X.). The Lake of Menteith resembles 
Loch Leven somewhat in outline, and in being relatively a very shallow 
basin. It is also historically related with Loch Leven, since Queen Mary 
at one time lived within their precincts ; the ruins of the Priory on 
Inchmahome, in which she resided before her removal to France, are of 
great architectural beauty and antiquarian interest. Its surface is only 
55 feet above the sea. Its maximum length is over 1J miles, and the 
maximum width over one mile, the mean width being five-eighths of a 
mile. Its waters cover an area of 652 acres (over one square mile), and 
it drains an area 6-J times greater, or over 4000 acres (nearly 6J square 
miles). The number of soundings taken in the Lake of Menteith was 
375, the maximum depth being 77 feet. A small portion of the bottom 



THE FRESH-WATER LOCHS OF SCOTLAND. 17 

thus falls below sea-level, as indicated on Plate X. The cubic mass of 
water contained in the loch is estimated at 562,000,000 cubic feet, and 
the mean depth at 19| feet, or 26 per cent, of the maximum depth. 
The length of the loch is 110 times the maximum depth, and 427 times 
the mean depth. 

The bottom of the Lake of Menteith is apparently very irregular. 
The 10-feet line follows approximately the outline of the loch, except 
that it is considerably removed from the south and south-east shores, 
where the land is bordered by reeds; it also surrounds the islands of 
Inchmahome, on which the Priory is situated, and Inch Talla, on which 
the castle is situated. Dog Isle, and a submerged crannog covered by 




FIG. 11. LAKE OF MENTEITH. 

(Photograph by G. W. Wilson.) 

four feet of water in the north-eastern angle of the loch at Port of 
Menteith. The area of the bottom covered by more than 25 feet of water 
is cut up into three portions. The eastmost of these 25-feet depressions 
has a maximum depth of 48 feet ; the central 25-feet depression is almost 
triangular in outline, with a maximum depth of 49 feet. The westmost 
25-feet depression is the largest and the deepest : it is almost divided 
into two halves by a narrow constriction between Inch Talla and Stable 
Point, the deepest water observed in the southern half being 49 feet, 
while the northern half contains the deepest water found in the loch. 
Here the bottom falls below the depth of 50 feet over an area of nearly 
32 acres, the 50-feet depression being about a third of a mile in length 
and over a sixth of a mile in maximum width. It encloses a small patch 

c 



18 BATHYMETRICAL SURVEY OF 

in which depths of 75, 76, and 77 feet were observed the maximum 
depth of the lake situated comparatively close to the northern shore 
at Coilledon. 

The area of the bottom between the shore and the 10-feet line is 
about 223 acres, or 34 per cent, of the whole area of the loch; that 
between the 10- and 25-feet contours is about 255 acres, or 39 per cent. ; 
that between the 25- and 50-feet contours is about 142 acres, or 22 per 
cent. ; and that over 50 feet nearly 32 acres, or 5 per cent. 

Loch Leven (see Plate XI.). Loch Leven has long been famous for 
its trout. In the old Statistical Account of Scotland* we read : ' The 
high flavour and bright red colour of the trout seem evidently to arise 
from the food which Nature has provided for them in the loch. What 
appears to contribute most to the redness and rich taste of the Loch 
Leven trout is the vast quantity of a small shellfish, red in its colour, 
which abounds all over the bottom of the loch, especially among the 
aquatic weeds. The trout when caught have often their stomachs full 
of them." 

About the year 1770 the trout brought about a halfpenny each, large 
and small, and perch a halfpenny per dozen. Some years later the price 
was doubled, and towards the end of the century the trout were sold at 
4d. per lb., pike 2d. per lb., and perch 2d. per dozen. In 1845 two 
boats and four boatmen were employed during part of the fishing season, 
while in 1891 there were twenty-two boats on the loch for the use of 
anglers. Extensive operations for the draining of the loch were com- 
pleted about the year 1845 at a cost of 40,000, by which the loch was 
lowered 4J feet, and the area reduced by about 1400 acres ; some people 
maintain that the quality of the trout has been injuriously affected by 
the draining. Prior to 1856 rod fishing was disappointing, but about 
that time, from some cause that does not appear to have been satis- 
factorily explained, the fish rose more freely to the bait, angling became 
more encouraging, and Loch Leven became a resort for anglers from all 
parts of the country. Some years ago the fishing was taken over by the 
Loch Leven Angling Association, Limited, who pay a rental of 1000 
per annum. The statistics regarding the trout caught by rod in the 
loch, and their weight, show great fluctuations from season to season. 
In 1872 over 17,000 were taken, the average weight being nearly 1 lb. ; 
in 1873 the take fell to 13,400, in 1874 to 6400, in 1875 to 5000, and in 
1876 even less. In 1877 the take rose again to 6000, in 1878 to 13,000, 
and in 1879 to 21,000, but the average weight seems to have been less. 
The best year recorded during the last quarter of a century was in 1888, 
when 23,516 trout were taken weighing 21,074 Ibs. In 1893, 1898, 
1899, and 1900 the takes again exceeded 20,000, but the weight never 

* Vol. vii. pp. 166, 168, 1793. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



19 



equalled the 21,000 Ibs. of 1888, the nearest approach being in 1893, 
when 23,100 trout, weighing 19,500 Ibs., were caught. Last year (1900) 
the trout taken by the rod numbered 23,811, weighing 15,584 Ibs., an 
average of 0'654 Ib. 

Perch are also abundant, and pike are not uncommon. Formerly 
charr were frequently taken, but they appear to have become scarce in 
recent years. The American weed (El odea canadensis) appears to have 
become firmly established in certain parts of the loch, and is causing a 
great deal of trouble, all the means hitherto tried for the purpose of 
destroying it being only of temporary benefit. 




FIG. 12. LOCH LEVEN AND CASTLE. 

(Photograph by J. Valentine.} 

On St. Serf's island (which is about 80 acres in extent) are the 
remains of a Priory dedicated to St. Serf, said to have been founded by 
a Pictish king, and given to the Culdees. The castle (on Castle island, 
which has an area of about 5 acres) is said to have been founded by 
Congal, son of Dongart, king of the Picts. It is famous in history as 
the prison in which the unfortunate Queen Mary was incarcerated for 
eleven mouths, and from which she effected her romantic escape. 

Considering the area covered by the waters of Loch Leven, it is an 
extremely shallow loch. When measured by the Ordnance Survey 
officers in August, 1893, its surface was found to be 349'6 feet above the 
level of the sea. In form it is somewhat pear-shaped, the greatest 
length being 3| miles from south-east to north-west, and the greatest 
width is about 2 miles. The mean width is nearly 1J miles, being 40 
per cent, of the length. Its waters cover an area of nearly 3400 acres 



20 BATHYMETRICAL SURVEY OF 

(5J square miles), and it drains an area nearly ten times greater, or 
about 32,500 acres (nearly 51 square miles). The number of soundings 
taken in Loch Leven was 538, the maximum depth being 83 feet. The 
bulk of water contained in the loch is estimated at 2,195,000,000 cubic 
feet, and the mean depth at less than 15 feet, being 18 per cent, of the 
maximum depth. The length of the loch is 232 times the maximum 
depth, and 1296 times the mean depth. 

An examination of the map shows how uneven the bottom of Loch 
Leven is. The deepest part of the loch is cut up into two portions, the 
larger depression lying to the west and south of St. Serf's island, with a 
maximum depth of 83 feet the greatest depth observed in the loch the 
smaller depression being situated in the north-western part of the basin, 
and attaining a maximum depth of 79 feet. The larger 70-feet depres- 
sion lies to the west of St. Serf, with two isolated soundings of 70 feet 
farther to the south-east ; the smaller 70-feet depression is in the north- 
western part of the loch, with an isolated sounding of 71 feet. The 
larger 50-feet depression to the south and west of St. Serf is nearly a 
mile in length, while the smaller in the north-western portion of the 
basin is a little over half a mile in length. The larger 20-feet depression 
is very irregular in outline, extending from near the outlet of the loch at 
the river Leven along the southern and western shores of St. Serf, and 
sending a wide branch in a westerly direction and another in a north- 
westerly direction towards Castle island, with an extreme length of 
about two miles. It is separated by an interval of about half a mile (in 
which the bottom rises in a pear-shaped elevation a sunken island 
covered by 5 to 9 feet of water) from the north-western 20-feet depres- 
sion, which is apparently extremely regular in outline, being about 
two-thirds of a mile in length, and over one-third of a mile in maximum 
width. The 10-feet line follows approximately the contour of the loch, 
except off the eastern shore to the north of St. Serf, where the 10-feet 
line runs on an average nearly three-quarters of a mile distant from the 
shore. The 10-feet line also surrounds Reed Bower, Castle island, and 
Scart island, and in addition to the elevation in the central part of the 
loch already mentioned, there is another small elevation covered by 
depths of 3 to 7 feet near the southern shore off Waterbutts plantation. 

The area of the bottom between the shore and the 10-feet contour- 
line is about 1430 acres, or 42 per cent, of the whole area of the loch ; 
that between the 10- and 20-feet contours is nearly 1450 acres, or 43 
per cent. ; that between 20 and 50 feet is about 375 acres, or 11 per 
cent. ; that between 50 and 70 feet is nearly 110 acres, or 3 per cent. ; 
and that over 70 feet is about 25 acres, or 1 per cent. It will thus be 
seen that no less than 85 per cent, of the bottom is covered by less than 
20 feet of water, and the mean depth as already mentioned is less than 
15 feet. 

The details regarding the physical features of the different lochs are 
collected together in the following table for convenience of reference : 



THE FRESH-WATER LOCHS OF SCOTLAND. 



21 



Ratio to 
area 
of loch. 



g s 

o O 

i 1 CO 



2 



s 

"0 

1 



5 . 



$ 5 8 2 



s r 

= .= < 
= 



111 



it C 
oe : . 9 ei 



= !* 

8 



f 



J 

ll 

W <5 



B 5^| 

(1 : = 

- i bJI 
^^ 



co op 

a- a 



a 



cccccccc 



^ o o o o o 



3-8 



a -a 



1-8 



? ? ^ ? 



t- (N CC ^ 

5 01 ^H cc 



J I 

E^^ 

s I 






S a 8 I 






ij 



311 



1 



i s 
11 



rl 
1 1 



. 

1 3 



a 



I 



22 BATHYMETRICAL SURVEY OF 

From the table on previous page it will be seen that in the thirteen 
lochs over 3800 soundings were taken, and that the aggregate area of 
water-surface is about 17 square miles, so that the average number of 
soundings per square mile is 225. The aggregate volume of water 
contained in the lochs is estimated at 36,543 millions of cubic feet. The 
area drained by these lochs is about 228 square miles, or about 13 times 
the area of the lochs. 

Deposits. As a general rule, the materials forming the deposits in 
these fresh-water lochs become finer grained the further from the shore 
and the deeper the water. Off the mouths of rivers and burns there is 
frequently a considerable accumulation of gravel and fine sand, extend- 
ing for some distance into the lake and occasionally reaching rather 
deep water. Large stones, gravel, and sand are usually found all round 
the shores within the limits of wave-action. The height and length of 
the waves, and the depth to which wave-action extends, depend on the 
size and depth of the loch. 

The central parts of the lochs are occupied by a fine impalpable mud, 
which is found in its most characteristic form in the greater depths far 
from shore ; it is usually of a light or dark brown colour, and sometimes 
there are indications of different-coloured layers. The usual mineral 
species are quartz, felspars, black and white mica, amphibole, pyroxene, 
magnetite, garnets, &c. Chemical analysis showed that these fine muds 
contained no appreciable calcareous matter, but traces of sulphuretted 
hydrogen were always present. The loss on ignition after drying at 
90 C., due to organic matter and combined water, varied from 13 to 
26 per cent. Diatoms were observed in nearly all the samples, and 
vegetable fibre was usually present in greater or less abundance. 

The samples from the deepest part of Loch Ka.trine were brownish, 
fine-grained homogeneous muds, with glittering mica-flakes, consisting 
principally (50 to 70 per cent.) of angular mineral particles exceeding 
0-05 mm. in diameter, the mean diameter being about 0-15 mm., with 
clayey and vegetable matter, and many minute mineral particles less 
than 0'05 mm. in diameter. A few diatoms were observed, and one 
sample, after drying at 90 C., gave 19' 91 per cent, loss on ignition. 

The mud from the deepest part of Loch Achray was of a grey-brown 
colour, containing much vegetable and clayey matter, the mineral 
particles exceeding 0'05 mm. in diameter making up probably 30 or 40 
per cent, of the whole deposit. Some fine diatoms were observed, and 
the loss on ignition, after drying at 90 C., amounted to 12'84 per cent. 

The mud from a depth of 102 feet in Loch Vennachar was yellowish- 
brown in colour, containing about 20 per cent, of mineral particles 
with a mean diameter of O'l mm., but principally made up of 
amorphous clayey matter with vegetable matter, and many minute 
mineral particles less than 0'05 mm. in diameter. There were a few 



THE FRESH- WATER LOCHS OF SCOTLAND. 23 

diatoms; the loss on ignition, after drying at 90 C., amounted to 
14 per cent. 

The mud from the deeper part of Loch Drunkie was of a dirty brown 
colour, containing 10 to 20 per cent, of mineral particles with a mean 
diameter of O'l mm., but consisting principally of amorphous clayey 
matter, with many small mineral particles, and vegetable matter. A 
few diatoms were observed. The loss on ignition, after drying at 90 C., 
amounted to 26'38 per cent. 

The deposit from the deeper parts of Loch Arklet was similar to that 
from Loch Drunkie, with even a larger quantity of vegetable matter. 

The mud from the deeper parts of Lochs Doine and Voil was of a 
brown colour, with 30 to 40 per cent, of mineral particles, and clayey 
and vegetable matter, and a few diatoms. A sample from a depth of 
80 feet in Loch Voil, after drying at 90 C., gave 22'74 per cent, loss on 
ignition. 

The material from a depth of 136 feet in Loch Lubnaig was a brown 
impalpable mud, with 30 to 40 per cent, of mineral particles, much 
clayey and vegetable matter, and a few diatoms.. The loss on ignition, 
after drying at 90 C., amounted in one sample to 16'29 per cent., and 
in another sample to 15-76 per cent. 

Three brown muds were examined from Loch Chon, from depths of 
10 feet, 14 feet, and 37 feet. The colour was lighter, and the mineral 
particles were more abundant and larger, in the shallower water. In 
the deposit from 10 feet the mineral particles made up probably 35 
to 40 per cent., and included a few rock fragments which sometimes 
attained a diameter of 10 mm., the mean diameter of the mineral 
particles exceeding O'Oo mm. in diameter being about 0'3 mm., while in 
the deposit from 37 feet the percentage falls to about 10, with a mean 
diameter of O'l mm. Inversely, clayey matter and vegetable matter 
were more abundant in the deeper water, mixed with minute mineral 
particles, impregnated with ferric oxide, and containing diatoms, 
Sponge spicules, arenaceous Foraminifera, and Entomostracous skeletal 
fragments. 

A sample from the deepest part of Loch Ard was a dark-grey mud, 
consisting principally of vegetable and clayey matter, the mineral 
particles not exceeding 10 per cent., with a mean diameter of about 
O'l mm. The organic remains observed were the same as in Loch Chon. 

A fine-grained dark-brown mud from a depth of 60 feet in Loch 
Leven contained probably not more than 5 per cent, of mineral particles 
exceeding 0'05 mm. in diameter, the bulk of the deposit consisting of 
clayey and vegetable matter, containing many beautiful diatoms, with 
Sponge spicules and Entomostracan remains. 

Temperature Observations. During the various visits to the different 
lochs, many observations were made on the temperature of the water, 



24 



Loc 
nbna 



BATHYMETRICAL SURVEY OF 

^ t^* Oi CO CO 00 OO 



o 

ju 

p co . cp 

""3 on CO " " " 

O m ..) 

_ ^H . O GO 

4* : : : co : 61 

o o >o 

JO >o >t >t 

00 CO G^l ( 

gs 8 ; ; ; s ; 3 

.^ cf 

-J5^ 

II 

Q 

w" 

"^i- *P . . .P . . 

3S 10 ' 10 

1-5 

<N(N..p.Oi ...P. 

o^.,,!,!!^!^ :::<N : . 

p . p , QO . p . . >p .cp . op p 

^ T 1 ^ .^"* . W T* . .** .^pip? 5 ? 5 ^!^ . . .pop 

- ^ - . .p 
p 

^ . "? . ? . *p . . ^p . *p . ^ . *p 

'ib : : : oo : ^ : : : c^i : : c^i : ^ : ^ : >-H 

00 lr^ CO ^O ^ CO CO 

o 
^r^ 

Ip _ < __ ip . . p p 

co : : :^ : :^H :^j 



%sl 

a a 






-H (N CO 1C OO O O 



THE FRESH- WATER LOCHS OF SCOTLAND. 25 

both on the surface and at intervals below the surface, down to the 
bottom. All the serial temperatures taken in Lochs Katrine, Arklet, 
Achray, Druiikie, Vennachar, Doine, Voil, and Lubnaig have been 
collected together in the table,* and, in order to make the record more 
complete, the temperatures taken by Jardine in 1812 and 1814 in Loch 
Katrine are given in the first two columns. 

Locli Katrine. The surface temperatures taken in Loch Katrine 
during the seven days from June 5 to 11, 1897, are extremely interest- 
ing, as illustrating the effect of the wind. The range of temperature 
during this time was 12 J, from 45"3 to 57'8, the highest reading being 
observed at Trossachs pier on the evening of June 5, and the lowest at 
the same place on the evening of June 9. This was evidently the 
result of a strong east wind, which commenced to blow on the 6th, 
and continued from the same direction till the 9th, blowing the warm 
surface water before it from the east towards the west end of the loch, 
while colder water from below was drawn up to the surface at the east 
end of the loch to take its place. The gradual cooling of the water at 
the east end of the loch is well shown by the temperatures taken at 
Trossachs pier from day to day : thus at 6.30 p.m. on June 5 the 
temperature was 57'8; at 11.30 a.m. on the 6th it was 56'2; and at 
4 p.m. 55'3; at^7 a.m. on the 7th it was 49'2 ; at 10.30 a.m. on the 
8th it was 46'3 ; and at 7.15 p.m. on the 9th it was 45'3. By 9.30 
a.m. on the llth it had again risen to 50*1. The effect of the wind was 
also shown by a series of surface temperatures taken from the steamer 
on its way from Stronachlachar pier to the Trossachs pier on the evening 
of June 9 : thus at Stronachlachar the temperature was 52'6; near the 
waterworks, 52'0; near Letter, 49'6; near Brenachoil, 48'8 and 
48-0; near Ellen's isle, 47*4 and 47'0; and finally at Trossachs pier, 
45'3. It will thus be seen that it is very unsafe to rely on a single 
observation at one spot as giving a sure indication of the temperature of 
the surface waters of a loch as a whole at any given season. A year later 
(from June 4 to 9, 1898) the temperature of the surface waters of Loch 
Katrine was not observed to fall below 50. On November 26, 1897, 
the surface temperature varied only from 46 0< 8 to 47-4, and on April 
13 and 15, 1899, from 41'2 to 42*7. 

The serial temperatures in Loch Katrine are shown graphically 
in the accompanying curves (Fig. 13), which exhibit the march of tem- 
perature in the waters of the loch throughout the year. The curve for 
April shows that the water from top to bottom has a temperature rang- 
ing between 41 and 42 Fahr. In the two curves for June the heating 
effect of the sun on the surface layers is indicated, but in depths beyond 



* Temperature observations in the surface waters of some of the lochs under considera- 
tion have been taken by Mr. Thomas Scott, and the results published in the Annual Reports 
of the Fishery Board Jor Scotland. 



26 BATHYMETRICAL SURVEY OF 



20 fathoms the temperature has not been appreciably affected. In June, 
1898, the whole body of water in the loch was apparently slightly 
warmer than in the previous June. The November curve shows a great 
accumulation of summer heat in the layers down to depths of 30 and 35 
fathoms. By this time cooling has set in, and progresses slowly until 
the spring, when the whole of the layers assume the nearly uniform 
temperature indicated by the April curve. The temperature of the 
bottom of the loch in depths of 400 feet may vary one or two degrees 
from year to year, this variation being due to the strength of the winds 
and general character of the climate in different years.* The highest 



56 

o 
55 

5* 
53- 

o 

52 

c 
51- 



4-8- 



Temperature of LOCH KATRINE 



i i 
1 



APRIL 1899 

JUNE 1897 

JUNE 1898 

.NOVEMBER 1897 




3 5 10 15 2O 25 30 35 4-O 45 5O 55 6O 65 7O 75 80 82/ 

TAT H O M S 

PIG. 13. CURVES OF TEMPERATURE IN LOCH KATRINE. 



temperature recorded in Loch Katrine is 58-4, so that the range in the 
central parts of the loch throughout the whole year is probably about 
18 Fahr. 



* See Murray, " Some Observations on the Temperature of the Water of the Scottish 
Fresh-water Lochs" (Scottish Geographical Magazine, vol. xiii. p. 1, 1897). At noon on 
March 10, 1900, in calm and frosty weather, the temperature of the surface water of 
Loch Katrine, over the deepest part of the loch, was 40-3, at 10 feet 40-2; at all other 
depths down to 492 feet the temperature-readings were 40-0 and 40 1. On the same 
date the readings in shallow water were 39 -4. 



THE FRESH-WATER LOCHS OF SCOTLAND. 27 

Loch Arklet. Temperature observations taken in the centre of Loch 
Arklet on June 11, 1897, gave a temperature at the surface of 55-4, 
and at 5 fathoms 54-4 ; on April 13, 1899, the surface temperature was 
42' 7. Temperatures as high as 61 have been recorded in this loch, 
so that the annual range probably exceeds 29. 

LochAchray. Observations taken in June and November, 1897, and 
April, 1899, showed that the temperature of the surface waters varied 
from 41 in April to 59-5 in June, the temperature in November being 
46. An intermediate observation at 5 fathoms in the centre on June 
12, 1897, gave 53'5. The highest reading recorded at the surface of 
this loch is 64 0< 1, so that the annual range probably exceeds 32. 

Loch Drunkie. Observations taken on June 12, 1897, showed that 
the surface waters had a temperature of 57, and an intermediate 
observation at 5 fathoms gave 52'6. On April 14, 1899, the surface 
temperature was 42"4. 

Loch Vennachar. The temperature observations taken in June, July, 
and November, 1897, and April, 1899, showed that the temperature of 
the surface water varied from 41 in April to 56*5 in June, the tem- 
perature in November being 46 to 47, while the water of Blairgarry 
stream had a temperature of 42-2. Serial observations in the centre 
of the loch on June 10, 1897, showed a gradual fall in the temperature 
from 55-8 at the surface to 47-2 at 15 fathoms; while on April 11, 
1899, the temperature was practically uniform from surface to bottom 
at 42-5 to 42-7. 

Loch Doine. Observations taken on July 7, 1897, and April 10, 1899, 
showed that the temperature varied from 42 in April to 54 in July. 
Serial observations in the centre of the loch in July gave a temperature 
at the surface of 54, falling to 52-l at 10 fathoms, while in April the 
temperature was found to be nearly uniform from surface to bottom, 
ranging from 41-8 to 42'6. 

Loch Voil. Observations taken in July, 1897, and April, 1899, showed 
that the temperature of the surface water varied from 41-2 in April to 
56-5 in July. Serial observations taken on July 7, 1897, showed that 
in the centre of the loch the temperature at the surface was 55-0, at 
5 fathoms 54-0, and at 16 fathoms 54*5, while further down the loch 
the temperature appeared to be rather higher, viz., 56'0 at the surface, 
and 55-3 at 3 fathoms and 8 fathoms. Serials taken on April 10, 1899, 
showed that the whole body of water was practically uniform in tem- 
perature at about 42. 

For the sake of comparison, a few surface temperatures were taken 
at the head of Loch Earn on July 6, 1897, the temperature of the loch 
varying from 48 0> 8 to 49'2, while that of the streams flowing into the 
loch was 52-2. On the following day (July 7, 1897) the surface of Loch 
Voil near the shore had a temperature of 56 0> 4, and a little distance 



28 BATHYMETRICAL SURVEY OF 

from the shore 54- 6, while the water of the burn flowing into the loch 
had a temperature of 53- 6, and higher up the stream 53'l. It thus 
appears that the waters of Loch Voil were warmer than those of Loch 
Earn, and in the case of Loch Voil the stream feeding the loch had a 
lower temperature than the loch itself, while in the case of Loch Earn 
the streams were warmer than the waters of the loch. 

Loch Lubnaig. Observations were taken in Loch Lubnaig only on 
April 6 and 8, 1899, and showed that at that time the temperature of the 
water was nearly uniform from surface to bottom, the range being only 
from 41-8 to 42'7. 

From the point of view of temperature, the Scottish fresh-water lochs 
may be divided into those which freeze during hard winters, and those 
which never freeze. Those which freeze over in winter are shallow 
lochs, and when frozen the water-temperature beneath the ice is at the 
maximum density point of fresh water (39-l) or lower. In spring the 
temperature of these shallow lochs rises much more quickly through 
the heat of the sun, and the whole mass of water attains a higher 
temperature than in the case of the deeper lochs; they also lose their 
heat much more quickly in the autumn than the deep lochs, and con- 
sequently have a much wider range of annual temperature. In the deep 
lochs those with 400 or more feet of depth the temperature of the 
water never rises so high in summer, nor sinks so low in winter, as 
in the shallow lochs, and the range is much less. The temperature of 
the bottom water in some cases does not change more than 1 Fahr. 
from year to year, and in the deepest lochs it appears to be practically 
constant at all times and seasons; 40 is the lowest temperature that 
has been recorded at the bottom in any of these deep Scottish lochs, so 
that the maximum density point is never reached. In summer, autumn, 
and even early winter, it is possible, by observing the temperature of 
the surface and sub-surface waters, to form a fairly accurate idea of the 
depth of a loch, the temperature being higher the shallower the loch. 
The waters from a deep loch like Loch Katrine are much the best for 
the water-supply to a city, for in summer the temperature is relatively 
low and in winter it is relatively high. 

The serial temperature observations taken in Lochs Chon, Ard, 
Menteith, and Leven are given in the following table, but many tem- 
perature observations were taken at the surface, which are not, of 
course, included in the table : 



[SERIAL TEMPERATURE OBSERVATIONS. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



29 



Depth 


Loch 
Chon. 


Lochan 
Dubh. 


Loch Ard. 


Lake of 
Menteith. 


Loch Leven. 


in 
Feet. 


May 15, 

1900. 


May 15, 

1900. 


Aug. 6, 
1899. 


May 16, 
1900. 


May 14, 
1900. 


June 11, 
1900. 


June 22, 
1900. 


Sept. 1, 
1900. 




o 


o 


o 








o 











51-8 


547 


63-0 


51-7 


51-3 


587 


62-3 


58O 


5 


, 




... 


... 




58-4 


62-2 




6 


507 


51-1 


61-3 


51-4 


5M 


... 


... 




10 




... 






... 


58-0 


62-1 




12 






61-3 


50 : 5 




... 


. 




18 




>t 


61-3 


48-5 


.. 


... 


, 




20 


49-5 






... 


507 


57-5 






24 






61 ! 2 


48-3 




... 






30 






60-5 


477 


... 


57-4 


61 5 




35 


... 


47-6 


... 


... 




... 


. 




40 


48-6 


_ 






50-5 


56-6 






48 






50-1 


47-1 


... 


. 


. 




50 










_ 


56-5 


59-3 


57-3 


60 


48 : 5 




48 : 2 


46 : 9 


50 : 2 


56-3 


56-8 


56-6 


70 




.. 






... 


... 


56-2 


56-6 


76 


__ 










... 


... 


... 


90 




.. 


47-5 


46-5 




... 


... 




96 


... 




47-5 


46-5 * 


... 


... 




..< 


100 







... 


46-4 




... 


... 


... 



Loch Chon and Lochan Dubh. These lochs were sounded on the 15th 
May, 1900, when the surface temperature in Loch Chon varied between 
51-8 and 54-5 ; below the surface the temperature decreased gradually 
down to 48-5 at 60 feet, so that the range observed throughout the 
whole body of water was only about 6. In Lochan Dubh the surface 
temperature was slightly higher than in Loch Chon (54-7), while the 
temperature of the deeper water was observed to be about 1 lower 
(47 0> 6), so that in the small body of water contained in Lochan Dubh 
the range was greater than in the larger Loch Chon, viz., 7. 

Loch Ard. Loch Ard was visited on the 5th and 6th August, 1899, 
and again on the 16th May, 1900. The highest surface temperature 
(64- 6) was observed in the southern prolongation of the loch in August, 
the maximum temperature observed at the same time in the body of the 
loch proper being 63. It will be seen that the whole body of water 
was warmer in August, and that a drop of 10 was recorded between the 
depths of 30 and 50 feet, the extreme range of temperature from surface 
to bottom being 17. No steep gradient was observed in May, the 
temperature decreasing gradually from top to bottom, the extreme 
range observed in May being 8-7. 

Lake of Menteith. The Lake of Menteith was visited on the 7th 
August, 1899, and the 14th May, 1900. No serials were taken in 
August, when the surface temperature varied only from 62'2 to 63'2. 
In May the surface temperature varied from 51*1 to 52'2, and the 
temperature decreased gradually from surface to bottom, the range 
observed in May throughout the whole body of water being only 2 



30 BATHYMETRICAL SURVEY OF 

from 50'2 to 52-2 ; the extreme range shown by all the observations 
amounts to 13. 

Loch Leven. Loch Leven* was sounded on the llth, 12th, and 22nd 
June, 1900, and again on the 1st September and the 23rd October. A 
reading at the surface on the llth June at 5 p.m. gave 58 0> 7, and on 
the 12th June at 4.50 p.m. a temperature of 67'5 was observed a 
range of nearly 9 in one day. This reading of 67'5 may be specially 
referred to as being, so far as we are aware, the highest temperature 
hitherto recorded in the waters of Scottish lochs, the next highest 
reading being one of 65 observed by Mr. Scott at the surface of Loch 
Oich in August, 1897. In September the surface temperature ranged 
only from 57 to 58-5. We are doubtful as to the working of the 
thermometer made use of in the October visit, and the readings have 
therefore not been included in the table. 

The serials taken in June indicate the rapidity with which the waters 
of a shallow lake like Loch Leven become heated up in summer. During 
the eleven days between June llth and 22nd the whole body of water 
had acquired a higher temperature, amounting to about 4 in the upper 
layers down to 30 feet, to nearly 3 at 50 feet, and to half a degree at 
60 feet. But, while the body of water in a shallow lake absorbs heat 
more rapidly than that in a deep lake, it also loses heat more rapidly, 
and therefore the quantity of heat stored up in the waters of a deep 
lake may not be less than that stored up in the waters of a shallow lake, 
as Delebecquef seems to think. From a preliminary study of our tem- 
perature observations in the Scottish lochs we believe the reverse to be 
the case. For instance, Loch Katrine and Loch Leven are comparable 
as regards superficial area, but Loch Katrine is six times as deep as Loch 
Leven, and contains twelve times as much water; if the temperature of 
the water in the two lochs were taken simultaneously before and after a 
definite interval in summer, it seems probable that, while the tempera- 
ture in Loch Leven might have been raised much higher than in Loch 
Katrine, the amount of heat stored up, as represented by the number of 
cubic feet raised 1, would be found to be greater in Loch Katrine than 
in Loch Leven, and that the difference would bear some relation to the 
ratio between the bulk of water and the area of surface exposed to the 
rays of the sun. We shall endeavour to work this matter out in greater 
detail as our temperature observations accumulate, and we may return 
to the subject in a later paper. 

Biology. Tow-net and other observations show that the nature and 



* We understand that the temperature of the water of Loch Leven has been taken at the 
pier once a day (at 12 noon) during the five months of the fishing season for the past twenty- 
five years, but we have had no opportunity of examining the observations. 

f " La quantite* totale de chaleur emmagasine dans un lac variera d'autant moins que 
ce volume sera plus grand par rapport a cette surface " (Les Lacsjranqais, p. 150). 



THE FRESH- WATER LOCHS OF SCOTLAND. 31 

amount of the organic life in the fresh-water lochs are subject to great 
variation in the different lochs when compared with each other, and in 
the same loch at different seasons of the year. Large numbers of 
observations are being collected, and we may look for interesting results 
when these are in a state for discussion. Generally speaking, the 
pelagic fauna and flora are much more abundant in the warm summer 
months than at other times of the year, and are also more abundant in 
the shallow lochs than in the deep ones. In the spring months there is 
a great development of diatoms and other Phytoplankton, which render 
the water less transparent than at other times of the year. 

Mr. Thomas Scott has lately been comparing the fauna in several of 
the Scottish lochs at different seasons of the year ; some of his results 
for the lochs now under consideration may be noted. 

In Loch Katrine the Entomostraca and other invertebrates were 
scarcer than in the other lochs examined. Fourteen species are recorded, 
Bosmina longispina being the only species present in all the gatherings ; 
Leptodora was entirely absent from the gatherings collected during the 
colder months. Cyclops strenuus and Polyphemus appeared to be more 
frequent in the upper part of the loch, and Bosmina and Leptodora in 
the lower part. The sides of Loch Katrine do not generally present 
conditions very favourable to shore-dwellers, and an examination of the 
shore about Stronachlachar yielded scarcely anything that differed from 
the tow-net captures, while at the lower end the shore between the 
Trossachs pier and Ellen's isle yielded much better results. Here forty 
species of Crustacea were obtained, as well as one or two species of 
Mollusca, but they were all individually scarce. The Cladocera were 
more numerous in species in the warmer than in the colder months, 
while with the Copepoda the reverse was observed, though the difference 
was not so great.* 

In Loch Arklet, Holopedium gibberum, one of the most remarkable 
species of the Cladocera in Britain, was moderately common in the 
tow-net gatherings collected in September and November, 1897, and in 
June, 1898, it was abundant all through the water, but when the loch 
was visited in March, 1898, not a trace of Holopedium could be seen. 
In June, when Holopedium was so abundant, other species previously 
observed were either very scarce or absent, as if they had been more 
or less crowded out by this particular cladoceran. Eleven crustacean 
species are recorded, Daplinia being the only form obtained in all the 
gatherings ; Bythotreplies was observed in September and June, but not 
in November and March, and Leptodora occurred only in September. 
Infusoria (Ceratium, &c.) and micro-algae were much less frequent in 
June than in the other gatherings. Forty-two species of Entomostraca 
were obtained by hand-net round the shores of Loch Arklet, including 

* Scott, Seventeenth Annual Report of the Fishery Board Jor Scotland, pt iii. pp. 148-151, 1899. 



32 BATYHMETRICAL SURVEY OF 

a few comparatively rare forms; very few molluscs were observed in 
any of the gatherings.*" 

Twelve species of Entomostraca were captured by the tow-nets in 
Loch Achray, Diaptomus, Daphnia, and Bosmina being taken in all the 
gatherings. Holopedium, though common in September and June, was 
not observed in November and March ; Bythotre plies also appears to 
be subject to somewhat similar seasonal variation. Fifty species of 
Entomostraca and four species of Mollusca were obtained by the 
hand-net, and by dragging the tow-net for a short distance over the 
bottom of Loch Achray. Three rare species : Diaptomus wierzejskii, 
Lathonura rectirostris, and Monospilus dispar were obtained, and in 
June a green fresh-water sponge (Spongilla fluviatilis) appeared to be 
moderately common in some shallow parts of the loch.f 

Loch Vennachar contains a rich crustacean fauna, as well as other 
invertebrates, most of which are suitable for fish food. Of forty-five 
species of Crustacea recorded from Lochs Katrine, Achray, and Venna- 
char, thirty-five species were observed in Loch Vennachar ; thirteen of 
the species from Loch Vennachar were not observed in either Lochs 
Katrine or Achray; fifteen of the species were common to the three 
lochs. I 

Twenty-five species of Crustacea and four species of Mollusca are 
recorded from Loch Lubnaig, including a new cladoceran (Alona 
neglecta), and one or two species new to Britain. 

The following results were obtained by Mr. Scott in Loch Leven in 
1890, 1897, and 1898. || 

In June, 1890, Mr. Scott found the fauna to be abundant and varied 
Mollusca, Arthropoda, Annelida, and Protozoa being more or less 
common all over the loch. Mollusca were common and generally dis- 
tributed, except at that part of the loch called the " Shallows," the 
bottom of which consists of little else than fine sand, and is therefore 
not so suitable as a habitat for these organisms as where the bottom 
consists of mud or vegetable debris. Fourteen species of Mollusca were 
obtained, comprising five Lamellibranchs and nine Gasteropods. The 
more common forms were Sphcerium corneum, Pisidium fontinale, 
Valvatapiscinalis, and Planorbis cotitortus. The swan-mussel (Anodonta 
cygncea) appeared also to be frequent. 

The Crustacea were by far the most numerous and varied of the 
invertebrate fauna of the loch. Cladocera and Copepoda occurred 
in great profusion all over and through the water. Daphnice, were 



* Scott, Seventeenth Report of the Fishery Board for Scotland, pt. iii. pp. 143-146. 
t/6W.,PP. 153-156. 

J Scott, Fourteenth Report of the Fishery Board for Scotland, pt. iii. p. 167, 1895. 
Scott, Thirteenth Report of the Fishery Board for Scotland, pt. iii. p. 247, 1894. 
|| See Ninth and Seventeenth Annual Reports of the Fishery Board for Scotland, part iii., 
1890 and 1899. 



THE FRESH- WATER LOCHS OF SCOTLAND. 33 

most abundant. Cyclops, especially 6'. strenuus, was also. plentiful. 
Ostracoda were not so common in the loch itself as they were around its 
margin, particularly those parts that were more or less overgrown 
with vegetation, as round the north-east shore. Seventeen species of 
Ostracoda were obtained along this part of the shore; twelve species 
were obtained from the south shore, and only eight from the loch itself. 
Among the Cladocera the rare and interesting Leptodora Jiyalina 
occurred in considerable numbers; Monospilus tenuirostris was also 
frequent in tjie material collected at one or two places. The following 
were the common species: Gammarus pulex, Diaptomus gracilis, 
Cypria sertna, C. ophthalmica, Limnicythere sancti-patrici, Daphnia 
lacustris, Phurorus triynntUu8 y Cliydorus sphcericus. 

The larvae of insects were abundant in the loch, especially the larvae 
of the Iphemeridae. The Libellulidae and Phryganidae were also repre- 
sented in the larval stage more or less frequently. Some idea may be 
formed of the myriads of these organisms present in the loch when it is 
stated that a conspicuous ridge composed of cast-off skins of insect larvae, 
which had been washed ashore during the preceding stormy weather, 
extended along the margin of the loch for a considerable distance. The 
curious so-called " water-bears " (Tardigrada), now included in the 
class Arachnida, were common among the decaying vegetable matter at 
the bottom. Species of Notonectidae or " water-bugs," and of aquatic 
Coleoptera were also more or less common, though their distribution 
seemed to be more localised. 

The worms were represented by several species parasitic and non- 
parasitic. Among the former were Schistoceplialus solid us, obtained 
from the body -cavity of a Stickleback (Gasterosteus aculeatus), and a 
species of tape-worm (Bothriocephalus latus?), several of which were 
found in the alimentary canal of the trout, six specimens being taken 
from one fish. The heads of the parasites were fixed at the extreme 
end of the cceca or blind tubes of the stomach, and their bodies were 
so elongated as to extend well down into the intestine. Uusally one 
parasite occupied a ccecum. Tubifex rivulorum was very common in the 
loch. 

Rhizopoda were common all over the loch. Several forms were 
obtained in the dredged and hand-netted material; the more typical 
varieties observed were: Difflugia pyriformis, D. globularis (much 
less frequent than the first named), D. corona (appeared scarce), D. 
marsupiformis (of frequent occurrence). Diatomacea were abundant, 
especially in the deeper parts of the loch, and included a considerable 
number of species. 

Mr. Scott visited Loch Leven again in September and December, 
1897, and in March and June, 1898, when he found that the free- 
swimming Entomostraca, though very abundant, consisted mainly of 
the one species, Daphnia lacustris. Leptodora hyalina was moderately 



34 BATHYMETRICAL SURVEY OF 

common in the September gathering, but was not observed in any of 
the other three. Diaptomus gracilis was frequent in the gathering 
collected in December, but was scarce in the others. Bythotrephes 
longimanus, though present in both the September and June gatherings, 
was not observed in those collected in December and March. Cyclops 
strenuus, though present in all the gatherings, was scarce. 

A few male Daphnice were observed in the December gathering, but 
in none of the others ; females with pseudova were frequent in all the 
gatherings. When the loch was examined in June, 1890, both Daphnella 
brachyura and Polyphemus pediculus were observed in the tow-net 
gatherings, but neither of these species was obtained in any of the 
gatherings recently collected. Infusoria and micro-algae, which were 
moderately frequent on the first three occasions when the loch was 
examined, were quite abundant in the loch in June, but these minute 
forms did not appear to be generally diffused, apparently occurring in 
shoals, and being particularly plentiful to the south of Reed Bower. 

The examination of the shore yielded a much greater number of 
species than were captured by the tow-nets, but individuals were not 
nearly so numerous. Fifty-five species of Crustacea were obtained in 
the shore gatherings collected during the recent experiments. The 
records of species obtained when the loch was examined in 1890 include 
a few that were not observed in the recent gatherings (viz., Cypria 
ersculpta, Candona lactea, Ilyocypris triplicate, Bosmina longirostris, 
B. longispina), and if these and the species captured with the tow-nets 
be added, they increase the number of crustacean species to sixty-five ; 
it is quite probable that even this number will yet be added to when the 
loch comes to be more thoroughly examined. Only five species were 
observed in all the gatherings in 1890, 1897, and 1898, viz., Caniho- 
camptus staphylinus , C. minutus, Cypria ophthalmica, Candona 
Candida, Chydorus sphcericus. The species recently captured include 
one Amphipod (Gammarus pulex), and eighteen each of Copepoda, 
Ostracoda, and Cladocera. The largest number of species of Crustacea 
obtained in any of the recent shore gatherings from Loch Leven was 
in that collected on 13th June. This gathering yielded thirty-nine 
species, or only four less than the total number observed in the tow-net 
and hand-net gatherings collected in June, 1890. 

The Cladocera, as a whole, were scarcer in those gatherings collected 
in the colder months than in the others. It may also be stated that in 
March the level of the water was much higher than during any of the 
other visits, and this no doubt accounted, partly at least, for the great 
scarcity of Cladocera in the gathering collected at that time; the 
reduced temperature incidental to the season may also have had some 
influence in bringing about this result. 

Rainfall and Outflow. An attempt has been made to arrive at an 



THE FRESH-WATER LOCHS OF SCOTLAND. 



35 



approximation to the total amount of rain falling annually on the 
drainage areas of the lochs draining into the river Teith, although the 
available records are far from sufficient for the purpose. Dr. Alexander 
Buchan, F.R.S., has kindly supplied us with information regarding the 
readings of the rain-gauges at observing stations within, and in the 
vicinity of, the catchment-basins of these lochs. The positions of these 
rainfall stations, and the mean annual rainfall, are shown on one of the 
accompanying maps (see Plate III.), and further particulars will be 
found in the following table : 



Station. 


Height of 
rain-gauge 
above 
sea-level. 


Years observed. 


Mean annual 
rainfall in 
inches. 




Feet. 






Ardlui 


50 


1865-70 


115-10 


Firkin 


100 


1866-79 


98-38 


Arrochar 


15 


1864-98 


81-31 


Head of Duchray ... 


1800 


1854-98 


84-27 


Glengyle 


380 


1854-98 


92-25 


Top of hill, Loch Katrine tunnel 


830 


1861-98 


77-95 


Brig o' Turk 


270 


1854-98 


64-47 


Loch Drunkie 


420 


1861-98 


63-62 


Loch Vennachar ... 


275 


1861-98 


57-31 


Between Ben Ledi and Glen Finlas 


1800 


1854-98 


53-68 


The Gart .. .. 


230 


1872-98 


54-47 


Leny 


345 


1861-98 


54-23 


Blaircreach . 


460 


1893-98 


82-63 


Stronvar 


422 


1860-98 


75-49 


Lochearnhead 


320 


1866-84 


65-50 


Tyndrum 


792 


1858 61, 72-3, 76-7 


99-10 



Grouping these stations and their mean annual rainfall into those 
likely to represent the rainfall on the catchment-basin flowing out of 
Loch Vennachar, and those representing the rainfall on the catchment- 
basin flowing out of Loch Lubnaig, we arrive at an average rainfall of 
76-25 inches for the Loch Lubnaig catchment, the mean height of the 
rain-gauges being 538 feet above the level of the sea, and an average 
rainfall of 75*37 inches for the Loch Vennachar catchment, the mean 
height of the gauges being 528 feet. 

The entire catchment-basin flowing out of Loch Vennachar (i.e. the 
combined drainage-areas of Lochs Katrine, Achray, Drunkie, and Ven- 
nachar) is about 75-29 square miles, and the mean height calculated 
from the bulk of laud above the level of the lochs is about 704-185 feet ; 
the mean height of the surfaces of these fotir lochs above sea-level is 
33 H feet, so that the mean height above the sea of the entire catchment 
is about 1035-685 feet. The entire catchment-basin flowing out of Loch 
Lubnaig (i.e. the combined drainage-areas of Lochs Voil, Doine, and 
Lubnaig) is about 73*39 square miles, and the mean height above the 
level of the lochs is about 935-129 feet ; the mean height of the surfaces 



36 BATHYMETRICAL SURVEY OF 

of these lochs above sea-level is 412 feet, so that the mean height above 
the sea of the entire catchment is about 1347-129 feet. 

The usual practice among engineers is to add 2J per cent, of rainfall 
for each 100 feet of height above rain-gauges. Applying this rule to 
the Loch Vennachar catchment-basin, where we have an observed rain- 
fall of 75-37 inches at an average height of 528 feet, we must add 12-7 
per cent, for the additional 508 feet of mean height, making an 
average annual rainfall over the entire catchment of 84-94 inches. 
This would give an annual fall of rain on the entire catchment equal 
to 14,857,214,000 cubic feet. Applying this rule, in like manner, to 
the Loch Lubnaig catchment-basin, where we have an observed rain- 
fall of 76-25 inches at an average height of 538 feet, we must add 20 
per cent, for the additional 809 feet of mean height, making an 
average annual rainfall over the entire catchment of 91-5 inches. This 
would give an annual fall of rain on the entire catchment equal to 
15,600,760,000 cubic feet. 

There is another method of estimating the rainfall, without taking 
the mean height of the drainage-area into consideration. Supposing the 
usually accepted increase of 2J per cent, per 100 feet of height, and also 
the mean annual rainfall at the average height of the rain-gauges, to be 
approximately correct, it is possible to calculate the rainfall at any given 
height. For the Loch Vennachar catchment the probable rainfall at 
the same heights and intervals as the contour-lines on the Ordnance 
Survey maps has been calculated from the starting-point of the mean of 
the observing stations 75-37 inches at 528 feet. Thus at the surface of 
Loch Vennachar the rainfall would be about 70*5 inches ; at 500 feet 
above the sea, 75-2; at 750 feet, 79-9; at 1000 feet, 84-6 inches; and 
so on, adding 6J per cent, for each succeeding interval of 250 feet. 
Multiplying the area between any two consecutive contour-lines by 
the mean of the two figures calculated for the same two lines should 
give an approximation to the amount of rain falling on that area. The 
result as obtained by this method for the entire catchment-basin flowing 
out of Loch Vennachar is given in the following table : 

Cubic feet. 

Level of lochs to 500 feet, 16 - 53 square miles x 72'8 inches = 2,795,710,000 

500,, 750 10-67 x 77 '5 =1,921,117,000 

750 ,,1000 10-35 ., x 82-2 ,, =1,976,514,000 

1000 ,,1250 9-46 ,, x 86 '9 ,, =1,909,847,000 

1250 ,,1500 10-22 x 91 '6 ,, =2,174,874,000 

1500 ,,1750 7-86 x 96 -3 ,, = 1,758,47<>,<KX) 

1750, ,2000 ,, 5-94 ,, x 101 -0 =1,393,784,000 

2000, ,2250 ,, 3-06 x 1057 ,, 751,422,000 

2250, ,2500 ,, 0-99 x 110-4 ,, 253,917,000 

Over 2500 ,, 0"21 ,, x 115-1 ,, 56,154,000 

Total 14,991,815,000 

This result comes very near to that obtained from the calculation 



THE FRESH-WATER LOCHS OF SCOTLAND. 37 

based upon the mean height, which gave a total annual rainfall of 
14,857,124,000 cubic feet. 

Applying the same method to the entire catchment-basin flowing 
out of Loch Lubnaig, we arrive at the following result : 

Cubic feet. 

Levels of lochs to 500 feet, 6 '82 square miles x 74 '6 inches = 1,181,982,000 

500,, 750 7-15 x 77-9 =1,293,991,000 

750,, 1000 9-05 ,, x 82-7 =1,738,769,000 

1000,, 1250 ,, 970 x 87-4 = 1,969,568,000 

1-250,, 1500 9-89 x 92-2 =2,118,434,000 

1500 ,,1750 9-43 x 97 O =2,125,060,000 

17.50,, 2000 8-06 x 1017 ,, =1,904,337,000 

2000 ,,2250 6-64 x 106'5 =1,642,879,000 

J-J50,, 2500 3-30 x 111-3 = 879,148,000 

2500,, 2750 ,, 1-88 x 116'1 = 507,081,000 

_>7.->0 3000 1-02 x 120-8 = 286,256,000 

Over 3000 ,, 0-35 x 126 '6 = 102,941,000 



Total 15,750,446,000 

Here, again, there is a close agreement between the result obtained 
by this method and that calculated from the mean height, which gave 
a total annual rainfall of 15,600,760,000 cubic feet. 

A third method of estimating the amount of rain falling on any 
particular region is afforded by drawing lines of equal rainfall, measur- 
ing the areas between the lines, and multiplying by the mean annual 
rainfall. Where the lines are based upon sufficiently numerous records 
of rainfall at various heights, this method should give excellent results ; 
but in the cases under discussion the number of observing stations is 
small, and the majority of the rain-gauges are situated on the low-lying 
grounds, only two being placed at heights exceeding 1000 feet, both 
at 1800 feet : therefore the figures obtained in these cases are most 
probably below the truth. Nevertheless, we have attempted to lay 
down the lines of equal rainfall from the available records, as shown 
on the accompanying rainfall map (see Plate III.). The areas enclosed 
by the lines of rainfall have been measured with the planimeter, and 
the rainfall calculated for the Loch Vennachar catchment-basin, with 
the following results : 

Cubic feet, 

50 to 60 inches, 12 '35 square miles x 55 inches = 1,578,040 000 
60 70 28-97 x 65 = 4,374,714,000 

70 80 18-93 x 75 = 3,298 372,000 

80 ,, 90 8-55 x 85 = 1,688,400,000 

90 ,, 100 ., 4"21 , x 95 = 929,166,000 

100 110 ., 2-28 ,, x 105 = 556,175,000 

Total 12,424,867000 

In like manner, the rainfall has been calculated for the Loch 
Lubnaig catchment-basin, with the following results : 



38 BATHYMETRICAL SURVEY OF 

50 to 60 inches, 
60 ,, 70 ,, 
70 80 ,, 
80 90 
90 100 
100 110 ,, 

Total 12,737,328,000 

The results obtained by these three methods may be summarized 

Vennachar catchment. Lubuaig catchment. 

First method ... 14,857,214,000 15,600,760,000 

Second ... 14,991,815,000 15,750,446,000 

Third ... 12,424,867,000 12,737,328,000 







Cubic feet. 


3-79 square miles 


x 55 


inches = 484,272,000 


23-89 


x 65 


,, =3,607,591,000 


21 79 


x 75 


,, = 3,796,700,000 


19-02 


x 85 


,, = 3,755,928,000 


441 


x 95 


,, = 973,307,000 


0-49 


x 105 


,, 119,530,000 



Mean ... 14,091,299,000 c. ft. 14,696,178,000 c. ft. 

Since Loch Katrine has been made use of by the Glasgow Corpora- 
tion as the source of the water-supply to that city, a record has been 
kept of the amount of water flowing out of Loch Vennachar or rather, 
a record has been taken twice a day of the depth of water flowing over 
a weir at Coilantogle, from which the quantity of water discharged may 
be calculated. When the height of the water on the weir exceeded 5 
inches, the weir became a drowned weir, so that it was difficult to 
estimate the outflow, as there was a considerable velocity of approach, 
especially during floods. 

Mr. Gale has kindly supplied us with the readings, taken twice a 
day during the year 1869, of the depth of the outflowing water at 
Coilantogle, and from these figures the outflow has been estimated for 
that year at 9,572,000,000 cubic feet. The year 1869 was the driest 
year during a period of twenty-four years, and we are not satisfied that 
this computation can be accepted as a very correct estimate of the out- 
flow from this catchment-basin even for that year. It would have been 
interesting to have calculated the outflow for twenty-five years in the 
same way as we have done for the year 1869, and to have taken the 
mean. However, accepting the above estimate for the year 1869, and 
adding to it the quantity of water supplied to Glasgow for that year, 
which, from Mr. Gale's table showing the average amount of water 
supplied per day during the first six months of the years 1866 and 1871, 
may be taken at about 1,659,300,000 cubic feet, we find that the mean 
rainfall exceeds the outflow in this year by 

According to the first method 3,625,914,000 cubic feet. 

second 3,760,515,000 

third 1,193,567,000 



Or a mean of 2,859,999,000 ,, 

Leslie* made experiments for twenty consecutive years on the 



* See Jour. Scot. Met. Soc., vol. v. p. 108, 3878. 



THE FRESH- WATER LOCHS OF SCOTLAND. 39 

allowance to be made for absorption by vegetation and for loss by 
evaporation, and he calculated that the average annual amount of water 
absorbed and evaporated is equal to about 13 inches of rainfall. On 
this basis, and assuming for the present that the evaporation from the 
surface of the water is equal to absorption and evaporation from the 
land, the total amount of water lost through absorption and evaporation 
over the entire catchment-basin of Loch Vennachar would be about 
2,273,885,000 cubic feet per annum.* Comparing this figure with the 
figures given above showing the excess of rainfall over outflow, we 
observe that, according to the mean of the three methods, the difference 
between the rainfall and outflow is greater than would be accounted for 
by absorption and evaporation as estimated by Leslie, there being an 
excess according to the first two methods, and a deficiency according to 
the third method. 

The foregoing figures, calculated for the year 1869, show that the 
rainfall unaccounted for by outflow at Coilantogle, and supply of water 
to Glasgow, is according to the first method 26 per cent., according to 
the second method 27 per cent., and according to the third method 
8 per cent. : this percentage must be referred to loss by absorption, 
evaporation, and the loss of water through underground channels. 



NOTES ON THE GEOLOGY OF THE LOCH KATRINE DISTRICT. 

By Messrs. BEN. N. PEACH, F.R.S., and JOHN HORNE, F.G.S., from 
unpublished observations made during the course of the Geological 
Survey of Scotland. With Geological Map (Plate II.). Published 
by permission of Sir Archibald Geikie, D.C.L., F.R.S., Director- 
General of the Geological Survey of the United Kingdom. 

The lochs in this district to be first treated of, with the exception of 
Loch Arklet, lie within the catchment-basin of the river Teith above 
Callander. Though situated about a mile to the west of Loch Katrine, 
the small lake, Loch Arklet, drains into Loch Lomond. 

1. Geological Structure of the area embracing these Lochs. 

All the lochs, save the lower part of Loch Vennachar, lie within the 
territory of the crystalline schists of the Highlands, which are bounded 
along the Highland border by a powerful fault stretching from Stone- 
haven to the Firth of Clyde. As shown on the geological sketch-map, 
this dislocation extends from Aberfoil north-east by Leny to Luirgeann 
on the Kelty water. On the south-east side of this fault the strata 

* The evaporation from the surface of the lakes will, of course, exceed Leslie's figures 
for loss through absorption and evaporation. 



40 BATHYMETRICAL SURVEY OF 

belong to the lower Old Red Sandstone formation, comprising, next the 
fault, andesitic lavas and agglomerates well seen in the Kelty water. 
Further to the south-east there is a broad belt of conglomerate arranged 
in beds, which are inverted or vertical near the fault, and as the 
observer approaches the plain they dip towards the south-east and 
pass underneath the overlying red sandstones. 

On the north-west side of this great boundary fault of the High- 
lands there is a narrow strip of sedimentary rocks about half a mile in 
breadth, referred provisionally to the Arenig division of the Silurian 
system, and consisting of red and black shales, radiolarian cherts, lime- 
stones, and grits. 

To the north of this belt of doubtful strata, the whole of the area 
included in the geological map accompanying this paper is occupied by 
rocks grouped under the general term of the crystalline schists of the 
Highlands. The latter are arranged in a definite order, but as yet it 
is uncertain whether it indicates the original sequence of deposition. 
The groups are here given in apparent descending order 

7. Garnetiferous mica-schists. 

6. Loch Tay limestone with sills of epidiorite. 

5. Mica-schists with sills of epidiorite. 

4. Schistose epidotic grits (" Green Beds "). 

3. Ben Ledi grits, massive and sometimes schistose. 

2. Aberfoil slates with subordinate bands of grit. 

1. Leny and Aberfoil grit. 

For a distance of about 5 miles northwards from the great boundary 
fault, the members of groups 1 to 4 are arranged in more or less parallel 
belts or strips running south-west and north-east, the strata dipping 
at high angles to the north-west. The groups appear in consecutive 
order, the Leny and Aberfoil grit being exposed immediately to the 
north of the doubtful Arenig rocks, while the Aberfoil slates and Ben 
Ledi grits appear successively to the north. The schistose epidotic 
grits (group 4), which lie apparently at the top of the Ben Ledi grits, 
are developed still further to the north, being traceable from a point 
not far to the south of Ben Lomond, north-east by Loch Chon and the 
lower part of Loch Katrine, thence across the hills to Strathyre and 
Loch Voil. From the Braes of Balquhidder they can be followed north- 
wards to Glen Dochart, and they reappear in Glen Falloch in the 
extreme north-west part of the map. At the head of Loch Lubnaig 
and in the Braes of Balquhidder sills or intrusive sheets of epidiorite 
occur at no great distance from the " Green Beds." 

In the belt between Loch Chon and Loch Lubnaig the " Green 
Beds," together with the Ben Ledi grits, form a series of compound 
synclinal folds, the strata being inclined at high angles. To the north 
and west of the " Green Beds " the representatives of the Ben Ledi 



THE FRESH- WATER LOCHS OF SCOTLAND. 41 

grits reappear and cover a wide area, extending from Ben Lomond 
north-east by Loch Katrine and the heights surrounding the head of 
Loch Voil, northwards by Ben More and westwards to Glen Falloch. 
Throughout this extensive area the strata are inclined at gentle angles : 
in marked contrast with the structure along the Highland border 
already indicated. There is here a change, over part of the area at 
least, in the lithological characters of the Ben Ledi grit group. The 
strata become more schistose and micaceous, merging in places into 
mica-schists. The accompanying geological map shows generally where 
these grits still retain their massive character and where they merge 
into mica-schists. 

The outcrop of the Loch Tay limestone is indicated on the geological 
map, from which it will be seen that this limestone, together with the 
sills of epidiorite, is traceable from the upper part of Strathyre, by the 
Kirkton glen, to Luib, in Glen Dochart. 

In addition to the great boundary fault already referred to, 
separating the lower Old Red Sandstone from the crystalline schists, 
various faults trending N.N.E. and S.S.W. traverse the south-east 
part of the area under consideration. These are, in the main, branches 
of the great dislocation which has been traced across the Highlands 
for a distance of 60 miles, from Loch Vennachar by Loch Lubnaig and 
Loch Tay to Gflen Tilt. In common with the dislocation referred to, 
the branch faults have a down-throw to the west or north-west, and 
they shift for some distance the outcrops of the strata which they 
traverse. They are truncated by the great boundary fault of the 
Highlands, and may be of pre-Old-Red-Sandstone age. 

The existing valley-system of the basin of the Teith has been carved 
out of a table-land of crystalline schists of varying hardness. Though 
there is conclusive evidence of great erosion during the successive 
glaciations of the region, yet it is clear that the present valley-system 
must have been developed in pre-glacial time. There is one point 
connected with the geological structure of this region which has had an 
important bearing on the evolution of the valley-system. Along the 
Highland border, as already indicated, there is a great development of 
conglomerates, coarse pebbly grits, and greywackes, belonging partly 
to the crystalline schists and partly to the Old Red Sandstone. These 
strata, being vertical or nearly so, would be much less easily eroded 
than the gently inclined schistose rocks lying to the north-west. Such 
an arrangement would naturally lead to the formation of narrow and 
comparatively flat-bottomed valleys behind rocky gorges, the latter 
being cut through the vertical beds of hard grit and conglomerate 
along the Highland border. That this remarkable structure must have 
likewise contributed to the erosion of rock-basins during the glacial 
period will become apparent on a closer examination of the geological 
structure of the area traversed by the larger lakes. 



42 BATHYMETRICAL SURVEY OF 

In the case of Loch Katrine, which is the largest and deepest of the 
lochs under consideration, there is a great rocky barrier at its outlet due 
to the Ben Ledi grits. Here they form a belt over a mile in breadth, 
and give rise to the rugged scenery so characteristic of that region. 
They appear on the crags of the Trossachs at the mouth of the loch, on 
the crest and slopes of Ben Venue (2393 feet), 011 Ben Bhreac (2295 feet), 
and on the heights round Ben An (1326 feet). The strike of these hard 
and durable strata is E.N.E. and W.S.W. that is, at right angles to 
the outlet of the loch, and the beds are vertical or highly inclined. 

The potency of the Ben Ledi grits as a rocky barrier must have been 
considerably increased by the development of epidotic grits or " Green 
Beds " lying immediately to the north. The latter, though not so 
massive as the Ben Ledi grits, are hard and durable ; they are repeated 
by a series of compound folds for nearly a mile across the strike, their 
northern limit being near Brenachoil Lodge. Their trend is likewise 
north-east and south-west, and the beds are vertical or highly inclined. 

On both sides of Loch Katrine above Brenachoil Lodge the geological 
structure is widely different, for in this area the Ben Ledi grits, grey- 
wackes, and slates reappear in a highly schistose form, the strata 
dipping generally at low angles to the south-east. Over much of this 
region, as already indicated, the altered sediments merge into mica- 
schists owing to the development of mica. It is obvious that these 
materials would yield more readily to the agents of denudation than 
the massive pebbly grits of Ben Venue and the Trossachs. 

Loch Achray, which lies about a mile to the east of the outlet of 
Loch Katrine, is only about 88 feet below the level of the latter loch. 
A powerful fault or dislocation, trending north-east and south-west, 
crosses the head of the loch near the Trossachs Hotel, which brings the 
massive Ben Ledi grits to the west in contact with slates to the east. 
It is a true rock basin which has been excavated mainly in the group 
of less durable slates. 

Loch Vennachar is crossed by the great boundary fault, already 
referred to, along the Highland border, the floor of the eastern portion 
being composed of Old Red Sandstone conglomerate, while that of the 
western part is formed of grits and slates belonging to the crystalline 
schists. Though there is a covering of drift on both sides of the lower 
part of the loch, still this sheet of water forms a true rock basin, for the 
Old Red conglomerate is exposed in the river about 1200 yards below 
the outlet. 

Loch Drunkie presents several interesting geological features. On 
referring to the map it will be seen that an arm of this loch runs nearly 
east and west for upwards of half a mile ; the northern margin is com- 
posed of massive grits, while the southern margin and probably the floor 
of this branch of the loch is formed of less durable slates. Another 
arm of this lake runs N.N.E., in the direction of Loch Vemiachar, the 



THK KKKSH-WATER LOCHS OF SCOTLAND. 43 

eastern margin of which nearly coincides with the course of a fault that 
crosses Loch Vennachar to the east of Lanrick. 

The three lakes, Loch Doine, Loch Voil, and Loch Lubnaig, must 
have formed one continuous sheet of water in post-glacial time. Loch 
Doine is now separated from Loch Voil by two cones of alluvium, to be 
referred to presently. Loch Voil is separated from Loch Lubnaig by a 
narrow plain of alluvium 5 miles in length, the surface of Loch Lubnaig 
being 9 feet lower than that of Loch Voil. These lochs form isolated 
parts of a true rock basin. Below the outlet of Loch Lubnaig there is 
a prominent rocky barrier composed of the massive grit of Leny and 
Aberfoil, from half to three-quarters of a mile in breadth. The strike 
of this pebbly grit is north-east and south-west, and the beds are 
inclined to the north-west at high angles. 

Loch Lubnaig is traversed by several faults, to which special reference 
will be made in the sequel. The lower part of the loch coincides with 
the trend of two faults, which, in all likelihood, determined for some 

distance the course of the river in remote geological time. 



2. Glaciation. 

The glacial phenomena in the lake district of the basin of the Teith 
prove beyond doubt that, during the climax of the ice-age, the ice-shed 
lay to the north of the area now under consideration; that the ice- 
movement was more or less independent of the existing valley-system ; 
and that even the highest mountains were over-ridden by the ice. This 
great development was followed by a period of local glaciation, when 
the glaciers were confined mainly to the existing valleys, and when 
the boulder-clay or ground-moraine of the earlier period was largely 
removed. The upper limit of the valley glaciation is frequently defined 
by prominent lines of moraines strewn with boulders, which rise to a 
considerable height on the mountain-slopes. The evidence pointing to 
these conclusions may now be briefly summarized. 

On the watershed to the north of Lochs Doine and Voil, the trend 
of the ice-movement during the great glaciation, as proved by the striae, 
was S.S.E. Again, on the lofty watershed east of Loch Lubnaig and 
south of Loch Earn, between Ben Each (2660 feet) and Ben Vorlich 
(3224 feet), there is conclusive evidence that the highest mountains in 
that part of the lake district were overridden by the ice. There the 
mountains are composed of grits, and the striae are well preserved. On 
Ben Each the striae point S.E. ; on the col between that hill and Stuc a 
Chroin, S. 40 E. ; on the latter mountain about S.E., and on the slopes 
of Ben Vorlich, at a height of 2500 feet, the trend of the ice-markings is 
E. 40 S. In the tract between Loch Lubnaig and Loch Katrine similar 
evidence is obtained of a south-easterly movement at great elevations. 
For example, on Ben Vane (2685 feet), at a height of 2642 feet, the 



44 BATHYMETRICAL SURVEY OF 

striae point S. 15 to 20 E. ; on the north and west slopes of Ben Ledi, 
S. 35 E., and on the crest of that mountain, at a height of 2875 feet, 
the direction is S.E. In like manner the mountains guarding the outlet 
of Loch Katrine are glaciated to the summit. Striae occur on the top of 
Ben Venue at a height of 2386 feet, pointing S. 40 E. ; on Ben An, at 
an elevation of 1750 feet, E. 30 S. ; and on Ben Bhreac, to the west 
of Ben Venue, the direction of the ice-markings is S. 30 to 40 E. 
Again, on the watershed between Loch Voil and Loch Katrine, the 
evidence indicates a south-easterly movement during the great extension 
of the ice. For instance, at various points on Taobh na Coille, at 
elevations between 2000 and 2250 feet, the striae point S. 30 E., and 
on Meall Gaothach, S. 30 E. In the tract immediately to the south- 
west of Loch Katrine the trend of the ice-markings varies from S.S.E. 
to E.S.E. For example, on Maol Mor (2249 feet) about the 2000-feet 
contour-line, to the north of Loch Arklet, the direction is about 
S. 15 E. ; and on the crest of Ben Uaimhe, to the south of that loch, 
S. 10 to 15 E. Eastwards, throughout the tract between Loch Chon 
and the Trossachs, the trend is E.S.E. To the south of the lofty 
heights stretching from Ben Venue towards Ben Ledi, the direction of 
the striae is more easterly, thus showing that the ice, after crossing the 
high ground, was deflected more towards the east (see glacial striae on 
Plate II.). 

The general south-easterly movement of the ice during the great 
glaciation, throughout the lake district of the basin of the Teith, is 
confirmed by the dispersal of stones in the boulder-clay, and by the 
transport of erratics. Many of the boulders have been carried far from 
their source, and are now found on the tops of the highest mountains of 
the district, some even at greater elevations than the parent rock. 

To the east of Loch Lubnaig, on Ben Vorlich, at a height of 3000 
feet boulders of garnetiferous mica-schist are found resting on glaciated 
surfaces of pebbly grit. Again, on the same mountain, at a similar 
elevation, there are erratics of epidiorite and hornblende schist rocks 
which are associated with the Loch Tay limestone, and which must have 
been transported from lower ground to the north. Similar boulders are 
met with on Stuc a Chroin and on Ben Each. Again, in the boulder- 
clay on the slopes of Ben Ledi, blocks of hornblende schist occur, 
which must have been transported for some distance. On the south side 
of Loch Katrine, between Stronachlachar and the aqueduct of the 
Glasgow waterworks, boulders of quartzite and garnetiferous mica- 
schist, which are foreign to the basin of Loch Katrine, are found in the 
boulder-clay. Eastwards near Brenachoil Lodge, on the north side of 
Loch Katrine, there are blocks of black schist, like that which accom- 
panies the quartzite of central Perthshire, and which has not been 
detected within the catchment-basin of Loch Katrine. These examples 
are sufficient to prove that, during the climax of the glacial period, 



THE FRESH -WATER LOCHS OF SCOTLAND. 45 

the ice-movement was independent of the existing valley-system. 
Indeed, from the evidence furnished by the striae and the transport of 
boulders, it may be inferred that the minimum thickness of the ice- 
sheet during this period must have been not less than 3000 feet in the 
lake district of Perthshire. 

The boulder-clay or ground-moraine, which was laid down during 
the great glaciation, must have been extensive, for it is found at great 
elevations, and it sometimes attains a great thickness. For instance, in 
the lee of the ridge of Ben Vane, to the west of Loch Lubnaig, it 
reaches a height of 2290 feet, and in places it is over 100 feet thick. 
But a large part of this deposit was removed during the later glaciation 
by the valley glaciers, for the relics occur above the limits of the valley- 
moraines, the latter resting frequently on the solid rock. 

Only a brief allusion is necessary to show the development of the 
later glaciers. The striae produced by this later movement coincide 
generally with the trend of the existing valleys. But though this is 
true, there is evidence to prove that even the larger valley-glaciers were 
thick enough to overflow minor watersheds. For instance, the glacier 
which descended the basin of Loch Katrine was thick enough to override 
the low col between that loch and Loch Chon, while another branch 
passed westwards by Loch Arklet towards Loch Lomond. Another 
example of the same phenomenon might be quoted. The glacier which 
descended the basin of Loch Voil towards Loch Lubnaig was thick 
enough to overflow the col between Strathyre and Loch Earn, while 
another branch ascended Glen Buckie and joined the Loch Lubnaig 
glacier at Laggaii. 

Moraines are well developed in most of the valleys, and are fre- 
quently arranged in concentric lines, as in Glen Finglas, north of Brig 
o' Turk. On the south side of Loch Katrine, between the jetty and 
Glasahoile, the moraines are distributed in parallel lines along the 
shore of the lake. As already indicated, the upper margins of the 
valley-glaciers are defined by the moraines. 

3. The Soundings viewed in Relation to the Geological History of the 
Area, and with reference to the Origin of the Lakes. 

Loch Doine, Loch Voil, and Loch Lubnaig. Reference has already 
been made to the fact that, in post-glacial time, Loch Doine, Loch Voil, 
and Loch Lubnaig must have formed one continuous sheet of water, 
and that their subsequent isolation has been due to the deposition of 
sediment. 

Loch Doine has been separated from Loch Voil by alluvial cones 
laid down by two streams, one from the north at Monachylemore, and 
another from the south at Monachyle Tuarach. The 50-feet subaqueous 
line has been traced round the Loch Doine basin, and the deepest sound- 



46 BATHYMETRICAL SURVEY OF 

ing is 65 feet. At the head of this loch there is an alluvial flat that 
stretches westwards for 1J miles, formed by the Lochlarig river and its 
tributaries. The gradual silting up, which is in constant progress at 
the head of Loch Doine at the mouths of the Lochlarig river and Allt 
Carnaig, is well shown by the resultant curve in the 50-feet contour-line. 

That Loch Voil is merely a continuation of the Loch Doine basin is 
further proved by the soundings, for immediately to the east of the 
cones just referred to, the 50-feet contour-line is met with, and has been 
traced round both sides of the loch eastwards to about Ledereich a 
distance of about 2 miles. From this point eastwards the lake gradually 
shallows towards the alluvial flat at Balquhidder, where moraines occur 
within 400 yards of Kirkton and Stronvar Bridge. The deepest part of 
the lake is enclosed by the 90 -feet contour-line at the head of the loch 
near Monachylebeg, and the deepest sounding within this line is 98 feet. 

The trend of Lochs Doine and Voil roughly coincides with the strike 
of the crystalline schists in that district. It is oblique indeed, nearly 
at right angles to the movement of the great ice-sheet during the 
climax of glacial conditions, and it harmonizes with the course of 
the later valley-glacier. Several small faults occur on the Braes of 
Balquhidder, north of Loch Voil, and on the hill-slope south of Loch 
Doine, but these are of little structural importance. 

The long stretch of alluvium that separates Loch Voil from Loch 
Lubnaig has been laid down by the Calair burn in Glen Buckie, by the 
Kirkton burn at Balquhidder, and by various streams on both sides of 
Strathyre. The silting up now in progress at the head of Loch Lubnaig 
is well shown by the tongues of alluvium, on both sides of the Balvag 
river, that project for some distance into the loch and isolate small 
basins of fresh water. About half a mile north of Loch Lubnaig a 
moraine rises out of the alluvium, probably a fragment of the adjacent 
moraine on both sides of the valley. As the top of this moraine probably 
rose above the level of the ancient united lake, the depth of the latter 
near this locality could not have been very great. 

A glance at the chart of Loch Lubnaig will show that its floor is 
much more irregular than that of Loch Voil. This may be accounted 
for partly by the presence of alluvial cones formed by various streams, 
and by features connected with the geological structure of the basin. 

The deepest parts of this lake form two basins enclosed by the 
100-feet contour-line, one to the north and the other to the south of 
Ardchullarie More. The upper one, about 500 yards long, is 146 feet 
deep, and the lower one, about 900 yards long, is 108 feet in depth. 
Though now separated by alluvial detritus brought down by the Ard- 
chullarie burn from the north-east, and by the Dubh Shruith burn from 
the south-west, these basins were probably originally continuous. The 
powerful Loch Tay fault with a N.N.E. and S.S.W. course, and with a 
downthrow to the west, crosses Loch Lubnaig immediately to the south 



THE FRESH- WATER LOCHS OF SCOTLAND. 47 

of Ardchullarie More, and strikes the west margin of the lake near 
the spit of sand to be referred to presently (see Plate II.). The steep 
gradient on the west side of the lake to the north and south of this spit 
of sand coincides with the course of the Loch Tay fault. About a quarter 
of a mile to the west of the Loch Tay fault a minor dislocation, with a 
similar trend and downthrow, crosses the lake and follows the channel 
of the Dubh Shruith burn. Now the lower deep basin lies to the east 
or upthrow side of the Loch Tay fault, and the upper deep basin is 
on the west or downthrow side of the Dubh Shruith fault. These dis- 
locations doubtless produced brecciation of the strata along the lines of 
movement, which led to more rapid disintegration of the materials. 

Close to the north-west limit of the upper basin enclosed by the 
100-feet contour-line the loch shallows to 20 feet, and from thence 
north-westwards to a point opposite Bienacreag the depth increases to 
62 feet. Here there is a small basin enclosed by the 50-feet contour- 
line. 

At the lower end of the loch, on the east side, there is a steep 
gradient which coincides with a line of fault, having a downthrow to 
the west (see Plate II.). As already indicated, this dislocation together 
with the Loch Tay fault may have determined in part the course of the 
river in remote geological time. But an impartial consideration of the 
evidence furnished by the soundings shows that the faults cannot 
account for the erosion of the lake basin. The striking fact that the 
lower deep basin of Loch Lubnaig coincides with the upthrow side of the 
Loch Tay fault the most powerful dislocation traversing the crystalline 
schists of this area shows that this rock-basin must be ascribed to an 
erosive agent acting independently of the lines of fault. It has further 
been shown that Lochs Voil and Doine must have been originally con- 
tinuous with Loch Lubnaig. The deepest sounding in Loch Voil is 
98 feet, and in Loch Lubnaig 146 feet, and it is obvious that their 
erosion must be ascribed to a common cause. The upper part of Loch 
Lubnaig coincides roughly with the trend of the ice-sheet during the 
great glaciation, which, from the evidence adduced in the foregoing 
pages, must have attained a minimum thickness of 3000 feet. But the 
basin must have undergone further erosion by the large valley-glacier. 

About half a mile to the south of Ardchullarie More, on the west 
margin of Loch Lubnaig, there is a prominent spit of sand extending 
into the lake for about 100 yards. It occurs not far to the south of the 
bend in the lake, at the meeting-point of the waves produced by the 
prevalent westerly winds. By the action of the waves the sand is 
steadily borne outwards on both sides of the spit, and from the soundings 
it is clear that this feature projects far into the lake. Further, it must 
have been in process of formation when the loch stood at a higher level, 
for a section appears in the adjacent railway cutting, which shows the 
sloping layers of sand coinciding with the form of the spit. 



48 BATHYMETRICAL SURVEY OF 

Loch Lubnaig originally extended to a point below Coireachrombie, 
about three-quarters of a mile below its present outlet. This point has 
been silted up by the detritus laid down by the Stank and Anie burns. 
The original southern termination of the lake touched the rocky barrier 
formed by the Leny grit. It is worthy of note also, that the level of 
Loch Lubnaig has been lowered about 20 feet by the denuding action of 
the river Leny. 

Loch Katrine. For a distance of 4 miles, west from Brenachoil Lodge 
to Stronachlachar about the half of the total length of the loch this 
lake has a comparatively flat bottom, enclosed by the 400-feet contour- 
line. The deepest sounding in Loch Katrine, 495 feet, is at the eastern 
limit of this basin, nearly due south of Brenachoil. The chart shows 
that the soundings throughout this basin gradually increase in depth 
eastwards to Brenachoil Lodge. The position of the deepest sounding 
is of interest, seeing that the strata which form the floor of the lake at 
this point consist of schistose micaceous grits, to the north-west of the 
epidotic grits (" Green Beds ") and the Ben Ledi grits, the two latter 
groups having formed the great rocky barrier at and above the outlet of 
the lake. 

Near the upper end of the loch a rocky barrier crosses the lake from 
Portnellan by the Black island to Rudha Maoil Mhir an-t Salainn. The 
deepest sounding along this barrier is 90 feet, and the shallowest is 48 
feet. On its lower side the 100-feet contour-line well-nigh crosses the 
lake. Above it there is another basin over half a mile in length, the 
greatest depth of which is 128 feet, immediately in front of the rocky 
ridge just referred to. Westwards the lake shallows, and at its head 
it has been silted up for a distance of half a mile by the alluvium laid 
down by the Gyle river. 

Below Brenachoil Lodge the soundings show an uneven floor, due 
probably to ridges of rock rather than to morainic deposits, if we may 
judge from the geological features on both sides of the lake. Ellen's 
isle is composed of epidotic grits (" Green Beds "), and the promon- 
tories of Am Priosan partly of ' ' Green Beds ' ' and partly of Ben Ledi 
grits. The promontory between the pier and the sluice is formed of 
Ben Ledi grits. 

During the geological survey of that region several small faults were 
found to cross Loch Katrine, but these are of minor importance, and 
have produced locally a slight brecciation of the strata. It is a typical 
example of a rock basin. The deepest sounding occurs in the front of 
the great rocky barrier in the lower part of the lake, in accordance with 
what we might naturally expect on the theory of glacial erosion. 
Though the soundings prove the deepest part of the lake to be 131 feet 
below sea-level, yet this depth is in proportion to the vast thickness of 
the ice during the successive glaciations of the basin. 

Loch Achray. This lake forms one basin, the deepest part being 



THE FRESH-WATER LOCHS OF SCOTLAND. 49 

enclosed by the 90-feet contour-line, and the deepest sounding being 
97 feet. A fault, with a downthrow to the west, crosses the head of 
the loch at the Trossachs Hotel, which has produced considerable 
brecciatioii of the strata, a feature probably continued along the floor 
of the loch between the hotel and Achray. The greater part of this 
lake is on the upthrow side of the fault just referred to, and the basin, 
as already indicated, has been excavated mainly in slates. 

Loch Vennacliar. Between Loch Achray and Loch Vennachar there 
is a strip of alluvium, the difference in level between the two lakes 
being 6 feet. The successive terraces show that these two lakes 
originally formed one sheet of water, which stood at a somewhat 
higher level. Loch Vennachar contains one prominent basin, about 
2 miles in length, enclosed by the 50-feet contour-line. Within this 
limit there are two smaller basins, which fall below the level of the 
100-feet contour-line (see Plate V.). The deepest sounding is 111 feet, 
which occurs to the north-east of Invertrossachs, on the line of the great 
boundary fault along the Highland border, which has a downthrow 
to the south-east. West of this dislocation the floor of the lake rises 
sharply to a level of 20 feet below the surface. Westwards, however, 
near Lanrick, the depth increases to 50 feet, a feature which coincides 
with the course of two faults crossing the loch branches of the Loch 
Tay fault, ancl each having a similar downthrow to the west. Doubtless 
where the deep soundings coincide with lines of fault, the strata have 
been much shattered and crushed, which has led to the more rapid 
disintegration of the materials. But though these faults may have led 
to local modifications of the floor of the lake, they obviously do not 
account for the excavation of the basin. The long, narrow hollow, 
crossing obliquely these lines of dislocation, points to glacial erosion. 

Loch Drunkie. Reference has already been made to the geological 
features of this basin (see p. 42). In the western portion of the west 
branch, where the hollow has been scooped out of slates, a small part 
of the floor is enclosed within the 50-feet contour-line. The deepest 
sounding, 97 feet, occurs in the north branch of the lake in front of a 
ridge to the east, which rises to a height of about 150 feet above the 
loch. The direction of the striae at Loch Drunkie is E. 20 S., and 
the deepest sounding is found where the erosion must have been 
greatest. 

Loch Arklet. This lake lies across the path of the great ice-sheet, 
and coincides with the trend of the later movement (see pp. 44 and 
45). Both the north and south shores of this loch are surrounded by 
moraines, but though such is the case the stream flows over solid rock, 
where it leaves the alluvial flat 1J miles west of the outlet, and con- 
tinues to flow for half a mile over solid rock. Originally the lake must 
have extended westwards to this barrier, for the intervening strip cf 
alluvium has been laid down by the burns joining the Arklet water not 

E 



50 BATHYMETRICAL SURVEY OF 

far from the outlet. On this flat there are moraines rising up in the 
midst of the alluvium. The greatest depth of the loch is 67 feet. At 
the upper or east end, where the loch is shallow, two islets appear, one 
formed of solid rock and the other of moraine matter. 

The soundings of the various lakes in the basin of the Teith above 
Callander, when viewed in connection with the geological structure 
and glacial phenomena of that area, furnish strong evidence in support 
of the theory of their excavation by ice-action. It is probable that, 
though the lakes lie, as a rule, across the path of the great mer de glace, 
they may have been partially eroded by that ice-sheet; at the same 
time there can be little doubt that their final modification must have 
been produced by the large valley-glaciers. 

The other lochs surveyed may be briefly characterised as follows : 

Loch Chon. Loch Chon is a striking example of a rock basin. The 
upper portion of the lake is floored by mica-schists, and the lower 
portion by the Ben Ledi grits and schistose epidotic grits (" Green 
Beds "), the members of the two latter groups being repeated by sharp 
folds. The trend of the loch N.N.W. and S.S.E. is oblique to the 
strike of the strata. At the head of the lake there is a broad alluvial 
flat, where it has been silted up for a distance of one-third of a mile by 
the detritus laid down by the adjacent streams. In the northern part 
of the basin the deepest soundings vary from 33 to 37 feet; but at a 
point about half a mile below the present head of the lake the depth 
increases from 40 to upwards of 60 feet. This feature coincides with & 
line of fault that crosses the loch in a north-east and south-west 
direction, its downthrow being to the south-east. From this point 
southwards for half a mile there is a narrow basin enclosed within 
the 50-feet contour-line, and within this basin there is a narrow trough, 
about 100 yards long and upwards of 75 feet deep, near the west 
margin of the lake. There is ground for the belief that nearly the whole 
of the basin bounded by the 50-feet contour-line is floored by mica- 
schist. 

About a mile below the head of the lake the soundings prove a 
remarkable decrease in the depth, the 25 -feet contour-line near the 
Heron islands being deflected towards the centre of the loch. The 
shallowing of the basin here takes place along the outcrop of very 
massive epidotic grits (" Green Beds "), several glaciated rocky islands 
appearing along this line. Southwards to the mouth of the lake there 
are alternations of Ben Ledi grits and schistose epidotic grits, the 
narrowest parts of the lake coinciding with the exposures of the latter 
group. 

About 100 yards below the outlet of the lake a prominent band of 
schistose epidotic grits occurs, which evidently formed a rocky barrier 
during the glaciation of that region. Beyond this outcrop there is a 



THE FRESH- WATER LOCHS OF SCOTLAND. 51 

small shallow basin, about 41 feet deep (Lochan Dubh), floored by 
schistose grits, which is traversed by a fault trending north-east and 
south-west, with a downthrow to the east. Across the mouth of this 
basin a band of massive, pebbly grits of the Ben Ledi type has been 
traced. 

A reference to the geological map will show that the direction of the 
ice-flow during the great glaciation coincides generally with the trend 
of the loch, striae being found on the rocky islands as well as round the 
margin of the lake. The evidence supplied by the soundings tends to 
support the theory that the basin-shaped hollow has been eroded by 
ice-action. The dislocations referred to above have doubtless produced 
local modifications of the floor of Loch Chon and of that of the small 
basin (Lochan Dubh), but they do not account for the excavation of the 
basin. 

Loch Ard, Loch Ard is also a true rock basin, which lies along the 
outcrop of a belt of slates between two bands of grit, the deepest part 
of the loch, as proved by the soundings, coinciding with the outcrop of 
the slates. 

From the Mill of Chon downwards to the head of the lake there is 
a small alluvial flat pointing to the former extension of the loch in that 
direction. At the upper end the soundings show that the average depth 
is 25 feet, with the exception of one small depression opposite Ledard 
burn, reaching 57 feet in depth. Eastwards, where the loch becomes 
narrower, the depth increases. The basin enclosed by the 50-feet 
contour-line is 1J miles long, while that surrounded by the 100-feet 
contour-line is three-quarters of a mile in length, the deepest sounding 
being 107 feet. 

The dislocation, with a downthrow to the east, that crosses the loch 
in line with Allt-na-Sgeith in a north-east and south-west direction has 
not produced any local modification of the floor of the lake, if we may 
judge by the soundings. The 100-feet basin crosses this fault without 
any apparent increase in depth on the side of the downthrow, which is 
probably due to the fact that the dislocation brings slates into contact 
with slates. The band of massive grit which forms for a long distance 
the southern margin of the loch evidently acted as a barrier during the 
period of glacial erosion. Crossing the lake at Briedach, this band of 
grit forms the promontory south-east of Glashart. 

On referring to the geological map, it will be seen that the band of 
grit just described is followed southwards by slates, the outcrop of 
which coincides with an expansion of the loch at its outlet, the deepest 
sounding being 52 feet. About 600 yards to the east of the outlet the 
trend of the latter belt of slates is E.N.E., and here occurs another 
small basin upwards of 30 feet in depth. 

No ice-markings have been found round the margin of the loch or 
near it ; but about half a mile to the south of the upper end of the lake 



02 BATHYMETRICAL SURVEY OF 

the direction of the striae is E. 20 S., which coincides generally with the 
long axis of the loch. Reference has already been made to the more 
easterly movement of the ice as it left the mountainous region and 
approached the low-lying districts; the course of Loch Ard coincides 
with this easterly trend of the ice. 

From the evidence adduced it is obvious that the geological structure 
of the basin of Loch Ard has had an important influence in the develop- 
ment of its present features, the latter being adequately explained by 
the theory of glacial erosion. 

The Lake of Menteith lies in various superficial deposits, composed 
partly of boulder-clay and stratified beds of the 100-feet beach. It is 
within the area occupied by the Old Red Sandstone, and the solid rock 
is visible only at one locality, at Coilledon. Loch Leven likewise lies in 
superficial deposits. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



53 



LOCHS OF THE TAY BASIN. 

E 'tent of the Tay Basin. The whole area of the drainage basin of 
the Tay, including the estuary as far as a line joining Tents Muir Point 
with Monifieth, as measured with the planimeter on the 1-inch Ordnance 
Survey maps, is 2509*73 square miles.* Considerably more than one- 
fourth of this area drains directly into fresh-water lochs, of which there 




30 ng Milt 



FIG. 14. INDEX MAP OF THE TAT BASIN. 

are seventy, including some of the largest in Scotland Lochs Tay and 
Ericht, for instance, being over 14 miles in length, while eight of them 
exceed 2 miles in length. 



* Geikie (An Elementary Geography of the British Islands, London, 1888, p. 86) gives the 
drainage basin of the Tay as 2250 square miles and Lawson (The Geography of River Systems, 
London, N.D., p. 6) as 2400 [square] miles. According to Geikie, the Tay pours a larger 
volume of water into the sea than any other British river, and its drainage area is the largest 
in Scotland, and seventh in point of size in the British Islands, being exceeded by that of 
the Shannon in Ireland, the Thames, Severn, Ouse, Trent, and Great Ouse in England. 



54 BATHYMETRICAL SURVEY OF 

The river-systems, which arise in the most mountainous and 
magnificent regions of Scotland, may be divided into four principal 
branches, viz., the Garry branch (the most northerly), the Tummel 
branch, the Tay branch, and the Earn branch (the most southerly). . 

(1) The Garry branch rises on the flanks of Beinn Mholach, Beinn 
Bhoidheach, and Carn Beag an Laoigh, flowing by various streams 
into Loch Garry, thence by the river Garry into the river Tummel at 
Faskally, to the north-west of Pitlochry, receiving the waters of the 
Erochy at Struaii, and those of the Tilt at Blair Atholl. 

(2) The Tummel branch rises in the Black Mount, the westernmost 
of the sources of the Tay river-systems, flowing by the river Ba into 
Loch Buidhe, Lochan na Stainge, and Loch Ba, which receives the out- 
flow from Lochan na h-Achlaise, thence flowing into Loch Laidon, 
thence into Loch Eigheach an expansion of the river Gaur receiving 
the waters from Lochan Sron Smeur, and then flowing into Loch 
Rannoch, which receives the outflow from Loch Ericht, flowing finally 
into Loch Tummel, thence by the river Tummel into the river Tay at 
Logierait. 

(3) The Tay branch rises on the flanks of Ben Lui (Beinn Laoigh), 
and flows by the river Fillan into Loch Dochart and Loch lubhair, 
thence by the river Dochart into Loch Tay, being joined by the river 
Lochay at Killin just before entering Loch Tay ; the outflow from Loch 
Tay is carried into the estuary of the Tay by the river Tay, which is 
joined shortly after leaving Loch Tay by the river Lyoii, bearing the 
outflow from Loch Lyon, and further on (at Logierait) the river 
Tummel, bearing the outflow from the Garry and Tummel branches, 
still further on (at Dunkeld) by the river Bran, bearing the outflow 
from Loch Freuchie, still further on (at Cargill) by the river Isla, and 
still further on, shortly before reaching Perth, by the river Almond. 

(4) The Earn branch takes its rise at the heads of Glen Ogle and 
Gleann Ceann Droma, the two streams flowing into the west end of 
Loch Earn, which receives also the waters of the Ample burn, Beich 
burn, the Vorlich, the Tarkeii, and other smaller streams; the outflow 
from Loch Earn passes at St. Fillans into the river Earn, which receives 
the waters of the Ruchill and Lednock near Comrie, those of the Turret 
bearing the outflow from Loch Turret, near Crieff, and other smaller 
streams as it flows eastward to join the Tay at the head of the estuary. 

Loch Ericht (see Plates XII. and XIII.). Loch Ericht is a large 
Highland loch situated partly in Perthshire and partly in Inverness- 
shire, at a high elevation among the Grampians. It is one of the wildest 
and most magnificent lochs of Scotland, presenting all along its shores 
scenes of lonely grandeur and sublimity, the mountains rising from the 
water's edge to great altitudes, their sides scarred by mountain torrents. 
The surface, when measured by the Ordnance Survey officers in 1872, 






THE FRESH-NVATKK U>< Us OF SCOTLAND. 55 

was found to be 1153-4 feet above the level of the sea; it is thus one of 
the most elevated of the larger Scottish lochs. It is known to anglers 
as the home of large Salmo ferox, as well as of trout said to be equal 
in quality to those of Loch Leven. It trends in a north-east and 
south-west direction, and is broadest near the southern end, narrowing 
gradually towards the northern end. It is over 14J miles in length, 
and over one mile in maximum breadth; the mean breadth is about 
half a mile, being 3J per cent, of the length. Its waters cover an area 
of over 4600 acres (or nearly 1\ square miles), and it drains an area 
seven times greater, or over 32,000 acres (nearly 50 J square miles). 
The total number of soundings taken in Loch Ericht was 488, which 
show that it is a comparatively deep loch, the greatest depth observed 
being 512 feet. The mass of water contained in the loch is estimated at 
38,027,000,000 cubic feet, and the mean depth at 189 feet, being 37 
per cent, of the maximum depth. The length of the loch is 150 times 
the maximum depth, and 405 times the mean depth. 

The deepest part of the loch is in the southern broader portion, 
where, about 3 \ miles from the foot of the loch, there is a small central 
depression, about one-third of a mile in length, and covering about 
58 acres, in which the depths exceed 500 feet, the maximum being 
512 feet. There are two 400-feet depressions, the larger, about three 
miles in* length, reaching to about 1J miles from the southern end, 
and enclosing the 500-feet depression. Separated by about a quarter 
of a mile from the northern end of the large 400-feet depression is 
the second smaller isolated depression, in which the maximum depth 
is 410 feet. There are two 300-feet depressions, the larger in the 
southern portion of the loch, the smaller in the northern portion. The 
southern depression is over 4J miles in length, and encloses the deepest 
water in the loch. The northern s^maller depression is under one mile in 
length, with a maximum depth of 314 feet, and approaches to within 
2J miles of the head of the loch. There are two 200-feet depressions; 
the larger runs from within a mile of the southern end to more than 
half-way towards the northern end, being over seven miles in extreme 
length. It is separated from the northern 200-feet depression by an 
interval of 2J miles, in which the depth varies from 127 to 194 feet. 
The northern 200-feet depression is nearly 2| miles in length, approach- 
ing to within about 1J miles from the northern end, and enclosing the 
small northern 300-feet depression already mentioned. The 100-feet 
depression is a continuous area extending from within less than half a 
mile of the southern end to within less than a mile of the northern end, 
and is about 13 J miles in total length. The 50-feet depression follows 
approximately the contour of the loch. Opposite Loch Ericht Lodge 
an isolated sounding of 44 feet was observed between the 50- and 100- 
feet lines, and about H miles farther down, opposite the entrance of 
the Allt Camus nan Cnamh, another isolated sounding of 20 feet jyas 
taken, surrounded by deeper water. 



56 BATHYMETRICAL SURVEY OF 

The area of the bottom of the loch between the shore and the 
50-feet line is estimated at about 880 acres (or 19 per cent, of the total 
area of the loch), that between the 50-feet and 100-feet contours is 
estimated at 695 acres (or 15 per cent.) ; that between the 100- and 
200-feet contours is estimated at about 1160 acres (or 25 per cent.); 
that between the 200- and 300-feet contours at about 875 acres (or 19 
per cent.) ; that between 300 and 400 feet at 476 acres (or over 10 per 
cent.) ; that between 400 and 500 feet at about 474 acres (or over 10 
per cent.); and that over 500 feet at 58 acres (or 1J per cent.). 

It will thus be seen that Loch Ericht is of very simple conformation. 
The deeper parts are divided into two basins, by the constriction in the 
outline of the loch in the vicinity of Loch Ericht Lodge, where, in one 
place, it is less than a quarter of a mile in width, but even here the 
depth in the centre exceeds 100 feet. 

Deposits. The deposits from Loch Ericht are interesting because of 
the evidence of layers of different colours. At a depth of 50 feet a red 
sandy mud was obtained; at 112 feet the mud was white beneath and 
brown on top; at 124 feet it was all brown; at 153 feet all brown; at 
182 feet sandy and white ; at 184 feet white and brown ; at 245 feet the 
deposit was a light-coloured mud, with a thin brown layer one inch in 
thickness on the top; at 270 feet it was white below, black-brown 
above ; at 366 feet the mud was all dark brown ; at 385 feet there was a 
white clay or mud with a dark layer on the top; at 456 feet the mud 
was all black ; at 497 feet a section of black mud 5 inches in thickness 
was obtained; and at 510 feet the same black mud was found, without 
any trace of the lighter-coloured mud. 

The sand from 50 feet consisted largely of mineral particles (pro- 
bably 70 per cent, of the whole deposit) with a mean diameter of about 
0-6 mm., one or two rock fragments attaining a diameter of 7 mm. The 
remainder of the deposit consisted of clayey and vegetable matter, with 
minute mineral particles less than 0*05 mm. in diameter, Diatoms, 
Sponge spicules, and Entomostracous skeletal remains. The light-brown 
mud from 150 feet contained about 30 per cent, of mineral particles, 
with a mean diameter of 0'5 mm., the largest being 5 mm. in diameter, 
with clayey and vegetable matter, and organic remains as previously 
mentioned. The dark-brown mud from 366 feet contained only about 
10 per cent, of mineral particles (quartz, black and white mica, &c.) 
exceeding 0-05 mm. in diameter, the mean diameter being about 0-2 mm. 
Samples of the two different-coloured layers of mud from a depth of 
385 feet were submitted to analysis, with the following results : 

Bottom layer. Top layer. 

Organic matter lO'OO per cent 26 '8 per cent. 

Insoluble residue .. ... 73*70 ,, 57'6 ,, 

Iron oxide 13'64 ,, 17'2 ,, 

97-34 101-6 



THE FRESH- WATER LOCHS OF SCOTLAND 57 

These analyses seem to show that the upper layer contained more 
organic matter (presumably vegetable matter) and a little more iron 
than the lower layer. Microscopic analysis of the two layers indicates 
that the mineral particles were rather more numerous and larger in the 
top layer, while the clayey matter seemed to be more abundant in the 
lower layer. 

Loch Garry (see Plate XV.). Loch Garry* lies to the east of Loch 
Ericht, at a still higher elevation, and the scenery round about is very- 
wild ; the height of the surface of the loch above sea-level is not given 
on the Ordnance Survey map, but a height of 1326 feet is shown near 
the outlet, so that the level of the loch is probably about 1320 feet above 
the sea. In trend and in outline it somewhat resembles Loch Ericht, 
narrowing towards the northern end. It is over 2J miles in length, 
the maximum width being over a quarter of a mile ; the mean breadth 
is slightly under a quarter of a mile (being 9 per cent, of the length). 
Its waters cover an area of about 390 acres (three-fifths of a square 
mile), and it drains an area thirty-seven times greater (or about 22 J 
square miles). The total number of soundings taken in Loch Garry was 
141, the maximum depth observed being 113 feet. The mass of water 
contained in the loch is estimated at about 846,000,000 cubic feet, and 
the mean depth at nearly 50 feet (being 44 per cent, of the maximum 
depth). The length of the loch is 119 times the maximum depth, and 
260 times the mean depth. 

Loch Garry forms a simple basin, except that the bottom sinks into 
two depressions exceeding 100 feet in depth, separated by depths of 82 
to 93 feet. The larger but shallower depression is situated in the 
southern half of the loch, and is over a quarter of a mile in length, the 
maximum depth therein observed being 105 feet. The smaller but 
deeper depression is situated in the northern half of the loch, being only 
about one-sixth of a mile in length, and containing the maximum depth 
of the loch 113 feet. The 75-feet, 50-feet, and 25-feet depressions form 
continuous areas, following approximately the outline of the loch. The 
75-feet depression is nearly 1| miles in length, the 50-feet depression 
nearly 2 miles in length, and the 25-feet depression 2 J miles in length. 

The area of the bottom between the shore and the 25-feet contour- 
line is about 117 acres (or 30 per cent, of the total area of the loch); 
that between the 25- and 50-feet contour-lines is about 83 acres (or 21 
per cent.); that between 50 and 75 feet is almost the same; that 
between 75 and 100 feet is about 87 acres (or 22 per cent.) ; and that 
over 100 feet is about 19 acres (or 5 per cent.). 

Temperature Observations. The serial temperatures taken while 
sounding out Lochs Ericht and Garry in June, 1900, are given in the 

* This loch must not be confounded with the larger Loch Garry in Inverness-shire. 



58 



BATHYMETRICAL SURVEY OF 



following table, and those taken in Loch Ericht are shown graphically 
in the temperature section (Plate XIV.), since they are extremely 
interesting as illustrating the effect of the wind upon the distribution 
of temperature : 





Loch 
Garry. 


Loch Ericht. 


Depth 








1 






in feet. 




June 19, 


June 20, 


June 0, 


June 16, 


June 15, 


June 20, 




Juce 21, 


1900, * 


1900, 1J 


1900, 3} 


1900, 9J 


1900, 5J 


1900, 1 




1900. 


mile from 


miles from 


miles from 


miles from 


miles from 


mile from 






S. end. 


S. end. 


S. end. 


N. end. 


N. end. 


N. end. 




o 


o 


o 


o 


o 


o 


o 





57'0 


47-3 


49-0 


50-0 


500 


53-2 


55-1 


5 




47-0 


48-7 


497 I 






6 










,->()< 






10 


56-9 


47-2 


47 : 8 


49-5 






... 


25 










49-9 






30 


49-5 


46-1 


47 ; 5 


48 : 6 






54 -2 


40 








45-8 








50 




44 : 6 


44-7 


44-7 


44 : 8 




52 : 3 


60 


46-3 


43-4 




... 




... 


... 


75 




42-6 


43 : 2 








44 : 


98 




... 


... 


... 




41 5 


... 


100 




422 




42-9 


42 : 6 






105 


46-0 










... 




120 




... 


... 


... 




... 


427 


150 




41-3 












200 








41 : 


41-1 


... 




300 








40-7 


40'.-) 






400 








40-5 


40-5 




. . . 


500 








40-:> 


... 





Loch Ericht. Like Loch Katrine, Loch Ericht is said never to freeze 
over, and the surface temperature remains comparatively low through- 
out the summer. The surface temperatures taken in Loch Ericht 
during the visit from 15th to 20th June show a range of 10'4, viz., 
from 46- 6 to 57 ; the higher temperatures were obtained towards the 
northern end of the loch, and the lower temperatures towards the 
southern end of the loch. A glance at the temperature section (Plate 
XIV.), based upon the observations given in the table, shows that the 
warmer water was all collected towards the upper end of the loch, as 
the result of a south-easterly wind which blew at times during the six 
days that were devoted to the survey of the loch, colder water having 
been drawn up at the opposite end of the loch to supply the place of the 
warmer surface water driven before the wind. 

Loch Garry. Loch Garry was visited on the 21st June, 1900, when 
the surface temperature was found to vary from 57 at the south-west 
end to 59'4 at the north-east end, and this would seem to indicate a 
distribution of temperature similar to that observed in Loch Ericht, 
but since only one temperature series was taken, it is impossible to form 
an idea of the distribution of temperature throughout the whole body 
of water. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



59 



Rannoch Moor Lochs. No coach road in Britain probably passes 
through more magnificent scenery than that between the Bridge of 
Orchy and Ballachulish. About half-way between Iiiveroran Hotel and 
King's House Hotel the river Ba crosses the road, and to the west lies 
Corrie Ba, the sanctuary of the Black Mount forest, where no shot is 
ever fired, and consequently this splendid corrie is the home of the deer, 
the golden eagle, the fox, and other wild animals. Here also is the 
most westerly source of the rivers of the Tay basin. In rainy weather 
a large amount of water passes down the river Ba and other streams 
into the moor of Rannoch, and about a mile or two to the eastward of 
the road a large extent of the moor is flooded, and presents the 




FIG. 15. MOOR OF RANNOCH, SHOWING LOCH BUIDHE AND LOCHAN NA STAINGE. 
(Photograph by Sir John Murray.) 



appearance of a vast lake. In drier weather there are distinct basins, 
which have received the names of Loch Buidhe, Lochan na Stainge, 
Lochan na h-Achlaise, and Loch Ba (or A-baw), all of them situated 
in drift and encumbered with rocks and small islands; they are all 
shallow. These lochs all contain trout, and have boats on them; they 
belong to the Marquis of Breadalbane, and are strictly preserved. On 
Eilean Molach in Loch Ba the heron still breeds in large numbers, and 
formerly the osprey used to breed in the same place. In making the 
survey of these lochs, the staff were much obliged to Mr. M'Intyre, the 
head stalker to the Marquis of Breadalbane. 



60 BATHYMETRICAL SURVEY OF 

Loch Buidhe (see Plate XVI.). Loch Buidhe (or Buie) is very 
shallow, and in places covered with weeds, though its surface is 
practically free from islands. It is somewhat quadrangular, though 
irregular, in outline, the maximum diameter (or length) from east 
to west being about one-third of a mile, and the maximum breadth 
from north to south about a quarter of a mile, the mean breadth being 
about one-sixth of a mile. Its waters cover an area of about 35 acres, 
or one-nineteenth of a square mile, and it drains an area 222 times 
greater, or over 11 square miles. It is deepest towards the eastern 
shore, where the maximum depth (3 feet) was observed in several 
places, shoaling towards the western shore, off which the weeds are 
most abundant; the volume of water contained in it is estimated at 
2,265,000 cubic feet. It was surveyed on April 15, 1902, about 40 
soundings being recorded. The surface of the water was determined 
by the Ordnance Survey officers in 1897 as being 981 feet above sea- 
level. The temperature of the surface water at 7 p.m. on April 15, 
1902, was 48 Fahr. 

Lochan no, Stainge (see Plate XVI.). Lochan na Stainge (or 
na-Sting) is extremely irregular in outline, and includes three com- 
paratively large islands, as well as a number of small ones. Its 
length from north to south is over half a mile, the maximum breadth 
being two-fifths of a mile, and the mean breadth about one-seventh 
of a mile. Its waters cover an area of over 51 acres, or rather more than 
one-twelfth of a square mile, and it drains directly about two-thirds 
of a square mile, but, since it receives the outflow from Loch Buidhe, 
its total drainage area is nearly 12 square miles, or 147 times the area 
of the loch. The loch is divided into two portions by a barrier at the 
central constriction, on which there is only 1 foot of water, the 
maximum depth observed in the northern portion (between the large 
island and the northern shore) being 8 feet, while the maximum depth 
of the loch (14 feet) was found in the southern portion immediately to 
the south of the barrier referred to. The volume of water contained in 
the loch is estimated at 11,407,000 cubic feet, and the mean depth at 
5 feet. The loch is on the whole shallow, nearly 99 per cent, of its 
floor being covered by less than 10 feet of water. It was surveyed on 
April 19, 1902, 55 soundings being recorded. The level of the loch was 
not determined by levelling, but on the new edition of the Ordnance 
Survey map (1897) there is a spot-level of 972 feet on the southern 
shore near the inflow, and another of 968 feet on the northern shore at 
the outflow, so that the surface of the water is probably about 970 feet 
above the sea. The drift-marks around the loch showed that it some- 
times rises 5 feet higher than on the date surveyed, and during floods 
the whole valley looks like one loch, with knolls projecting above the 
water. The temperature of the surface water at i0.30 a.m. on April 



THE FRESH-WATER LOCHS OF SCOTLAND. 



61 



19, 1902, near the boathouse was 43, and on returning to the same 
place at 12.30 (noon) it had risen to 46*4; in the main basin, near the 
centre, the surface temperature was 42'6. 

Lochan na h-Achlaue (see Plate XVI.). Lochan na h-Achlaise (or 
na-Hachlich) is irregular in form, the outline being somewhat triangular 
or heart-shaped, with the apex pointing south. It includes many larger 
and smaller islands, and the bottom in the shallower places is covered 
by stones and boulders. The length from north to south is over four- 
fifths of a mile, while the maximum breadth from east to west is about 
three-quarters of a mile, the mean breadth being over one-third of a 




FIG. 16. LOCHAN NA H-ACHLAISE. 

(Photograph l> !f R. M. Clark. B.Sc.) 



mile. Its waters cover an area of about 183 acres, or nearly three- 
tenths of a square mile, and it drains an area of over one square mile, 
or nearly four times the area of the loch. The north-western portion 
of the loch is shallow, the deeper water being found in the southern and 
eastern portions. The 10-feet basin is a continuous area, extending 
from near the southern shore in a northerly and then north-easterly 
direction to near the north-eastern shore, excluding the islands lying 
off the eastern shore, and is nearly three-quarters of a mile in length. 
The 10-feet basin includes two 20-feet basins, the more southerly being 
the larger and deeper, the maximum depth of the loch (28 feet) having 



62 BATHYMETRICAL SURVEY OF 

been found towards the north-eastern end of this basin, and com- 
paratively close to the eastern shore. The volume of water contained 
in the loch is estimated at 76,236,000 cubic feet, and the mean depth 
at 9J feet. The loch is on the whole comparatively shallow, about 63 
per cent, of the bottom being covered by less than 10 feet of water, 
while only 9 per cent, of the bottom is covered by over 20 feet of water. 
The loch was surveyed on April 16, 1902, over 100 soundings being 
recorded. The surface of the water was found to be 962 feet above 
sea-level by the officers of the Ordnance Survey in 1897. The tem- 
perature of the surface water at 6 p.m. on April 16, 1902, was 45 0- 2. 

Loch Bd (see Plate XVI.). Loch Ba (or A-baw) is extremely 
irregular in outline, studded with large and small islands, and with 
many rocks and boulders. Its length from south-west to north-east in 
a straight line is over 2 miles, and following the axis of deep water 
about 2J miles. Its maximum breadth in the southern portion from 
east to west is over a mile, and the mean breadth is nearly half a mile. 
Its waters cover an area of about 585 acres, or nine-tenths of a square 
mile, and it drains directly an area of 4J square miles, but, since it 
receives the outflow from Loch Buidhe, Lochan na Stainge, and 
Lochan na h-Achlaise, its total drainage area is nearly 17^ square miles, 
or nineteen times the area of the loch. 

The bottom of Loch Ba is very irregular. The deepest water occurs 
in the northern portion between the islands of Eileaii Molach and 
Eilean na h-Iolaire, where there is a small basin less than a quarter of 
a mile in length, and over 20 feet in depth, the maximum depth of 
30 feet having been observed about one-sixth of a mile to the north of 
the northern point of Eilean Molach. An isolated sounding of 20 feet 
was taken close to the western shore of the southern portion of Eilean 
Molach. There are three irregular basins with depths exceeding 10 
feet : the central one, enclosing the 20-feet basin, and extending on both 
sides of Eilean Molach and to the west and north of Eilean na h-Iolaire, 
is nearly three-quarters of a mile in length and over a quarter of a mile 
in breadth ; the southern one, occupying the wide south-eastern portion 
of the loch, is nearly half a mile in maximum diameter ; and the third, 
situated in the north-eastern extension of the loch, is nearly half a mile 
in length and nearly a quarter of a mile in breadth. The volume of 
water contained in the loch is estimated at 206,497,000 cubic feet, and 
the mean depth at 8 feet, being 27 per cent, of the maximum depth. 
The length of the loch is 378 times the maximum depth and 1402 times 
the mean depth. Over 70 per cent, of the floor of the loch is covered by 
less than 10 feet of water, and only 1| per cent, by more than 20 feet of 
water. The loch was surveyed on April 17 and 18, 1902, over 300 
soundings having been taken. The level of the loch was' determined by 
the Ordnance Survey officers in 1897 as being 957 feet above sea-level. 



THE FRESH- WATER LOCHS OF SCOTLAND. 



63 



The temperature of the surface water near the boathouse, when com- 
mencing the survey at 2.45 p.m. on April 17, was 50'8 Fahr., but 
later on, out in the open water, the surface temperature was 44'2 
Fahr. ; on the 18th at noon the surface temperature near the shore 
was 50-0 Fahr., while in the bay to the north of the boathouse the 
temperature was 46-0 Fahr. 

Lochan Beinn Caorach and some other small basins of water in 




FIG. 17. HERONS' NESTS ON EILEAN MOLACH IN LOCH BA. 
(Photograph by T. N. Johnston, .!/.., C.M., F.R.S.E.) 



this region were without boats and could not be sounded; they were 
evidently all quite shallow and of the same character as Loch Buidhe. 

Loch Laidon (see Plate XVII.). Loch Laidon (or Lydoch, or 
Luydan) lies partly in Perthshire and partly in Argyllshire, the 
boundary running along the centre of the western arm and for a 
certain distance up the main loch. It is one of the best trouting lochs 



64 BATHYMETRICAL SURVEY OF 

in the district, or perhaps in Scotland. It is about 5J miles in length 
from north-east to south-west, but it sends out an arm towards the 
west, which is over 1J miles in length, and a line following the axis of 
the loch from the north-east end to the extremity of the western arm 
would be over 6 miles in length. Its maximum breadth is nearly 
three-quarters of a mile, and the mean breadth about one-third of a 
mile, or 6-4 per cent, of the length. Its waters cover an area of about 
1149 acres, or over 1| square miles, and it drains directly an area of 
30J square miles; but, since it receives the outflow from Lochs Ba, 
Achlaise, Stainge, and Buidhe, its total drainage area is over 47| square 
miles or 26J times the area of the loch. Nearly 500 soundings were 
taken in the loch, and the maximum depth observed was 128 feet, the 
mean depth being 35 feet, or 27 J per cent, of the maximum depth. The 
length of the loch is 219 times the maximum depth, and 795 times the 
mean depth. The volume of water contained in the loch is estimated at 
1,761,733,000 cubic feet. The western extension and the southern end 
of Loch Laidon are filled with boulders and islets, and are like Loch Ba 
in character, but the main basin is of comparatively simple form, 
though with minor undulations of the lake-floor, the deepest water 
occupying the centre of the loch, where there is a basin three-quarters 
of a mile in length and over 100 feet in depth, the maximum depth of 
128 feet having been observed about 2| miles from the south-west end 
and 2J miles from the north-east end. Separated from this main 
100-feet basin by shallower water, there is a sounding of 104 feet a short 
distance to the south-west, and half a mile further south there is an 
isolated sounding of 100 feet; there is also an isolated sounding of 100 
feet a quarter of a mile to the north-east of the main basin. The 
principal 50-feet basin extends from less than a mile from the south- 
west end to less than 1J miles from the north-east end, and is nearly 
3 miles in length. Separated from this larger basin by an interval of 
a quarter of a mile is a smaller one, about one-third of a mile in length, 
situated in the north-eastern part of the loch, and nearly midway 
between them is an isolated sounding of 50 feet. The western arm of 
Loch Laidon is shallow and filled with rocks and boulders, the greatest 
depth observed being 17 feet in three different places. Of the entire 
lake floor, 53 per cent, is covered by less than 25 feet of water, 21 per 
cent, is covered by water between 25 and 50 feet in depth, 22 per cent, 
by water between 50 and 100 feet in depth, and 4 per cent, by water 
exceeding 100 feet in depth. Loch Laidon was surveyed on April 9 to 
25, 1902, and the surface of the loch was found by levelling to be 923-9 
feet above sea-level. When surveyed by the Ordnance Survey officers 
on July 28, 1860, the level of the loch was 924-6 feet above the sea. 
At the north-eastern end of Loch Laidon is a small basin called Dubh 
Lochan, which was found by levelling on April 14, 1902, to be 2 feet 
higher than Loch Laidon, and should therefore, strictly speaking, be 



THE FRESH-WATER LOCHS OF SCOTLAND. 



65 



looked upon as a distinct lake, but in the foregoing description the two 
lakes have been regarded as one. Many temperature observations were 
taken in Loch Laidon on April 9, 10, 14, 15, and 25, the surface 
readings varying from 38'8 at 5 p.m. on the 9th to 48 0- 2 at the head of 
the loch at 1 p.m. on the 10th a range of 9-4 in the temperature of 
the water, while the range in the air-temperature during the same 
period was only 5 (from 45-2 to 50-2). Two serial temperature 
observations were taken in the centre of the loch, the first at 5 p.m. on 
April 9, when the readings were identical (39-8) at the surface and at 
depths of 5 and 25 feet, the second at 5.20 p.m. on the 10th, when the 




FIG. 18. LOCH LAIDON. 

(Photograph by Miss Marynret Murray.) 



surface readings were 39-8 and 41, that at 5 feet 39'7, and that at 
20 feet 39 0> 4. The surface temperature in Dubh Lochan on April 14 
was 43-9. 

The western arm of Loch Laidon receives the waters from a small 
loch (Lochan Gaineamhach) lying about 2 miles to the west. This 
loch, and the neighbouring "one to the north, were visited on May 20, 
1903, but, as there were no boats on tjiem, they were not sounded. 
They were found to be of the same general character as the other lochs 
of Rannoch Moor shallow, with stony shores, containing boulders 
and islets, some of the latter with small trees on them. In Lochan 
Gaineamhach, weeds were seen only in some very small bays, but in 



66 



BATHYMETRICAL SURVEY OF 



the other lochan weeds were seen in several places, with a little open 
water in the eastern half. 

To the north of the north-eastern end of Loch Laidon lies the 
little Lochan a' Chlaidheimh, where three counties (Perthshire, 
Argyllshire, and Inverness-shire) meet. This lochan was visited on 
May 14, 1902, but was not sounded, as there was no boat on it. It is 
evidently very shallow in all parts, full of rocks and boulders, a rock 
showing above water even in the very centre, and all along the shores 
rocks are numerous, extending in lines out from the shore. A couple of 
miles to the east of Lochan a' Chlaidheimh lies Lochan Sron Smeur, 
next to be dealt with, on which there was a boat. 




FIG. 19. LOCHAN SRON SMEUR. 

(Photograph by H. C. Lamb.) 



Lochan Sron Smeur (see Plate XVIII.). Lochan Sron Smeur (or 
Sron Smear) is situated a little to the east of the road running from 
Rannoch to Loch Ossian, and is said to contain small black trout, but 
is strictly preserved. It is over half a mile in length, less than a quarter 
of a mile in maximum breadth, the mean breadth being one-seventh of 
a mile, or 25 per cent, of the length. Its waters cover an area of over 
50 acres (or about one-twelfth of a square mile), and it drains an area of 
nearly two square miles, nearly twenty-four times the area of the loch. 
It was surveyed on May 12, 1902, the maximum depth observed being 
33 feet. The volume of water contained in the lake is estimated at 
22,592,000 cubic feet, and the mean depth at 10'3 feet, or 31 per cent, 
of the maximum depth. The loch is of simple conformation, the western 



THE FRESH- WATER LOCHS OF SCOTLAND. 67 

half being comparatively shallow, while the deeper water occurs in the 
eastern half, the maximum depth having been found about one-eighth of 
a mile from the eastern end. The 10-feet basin approaches quite close to 
the eastern shore, and is about one-third of a mile in length, enclosing 
the 20-feet basin, which is about one-fifth of a mile in length. About 
61 per cent, of the lake-floor is covered by less than 10 feet of water, 
while about 12 per cent, is covered by over 20 feet of water. No 
bench-marks were found near the loch, but a little distance up the river 
which feeds it there is a spot-level of 1134 feet. There was little 
evidence of much rise and fall in the level of the water, the range 
possibly not exceeding 2 feet. The temperature of the surface water 
varied from 47 0- 4 to 50'5, a range of 3'l, the higher readings being 
taken in shallow water near shore. Readings at 10 feet and at 20 
feet near the centre of the loch gave 48 in each case, the surface 
temperature at the same time being 47 : 6. 

Less than a mile to the east of Lochan Sron Smeur is Lochan Loin 
nan Donnlaich (or Lochan Loin nan Dubhach, or Loch-an-Londonich), 
said to contain large trout. When visited, many rocks and boulders 
were observed showing above the water, and grass filled the bay at 
the outlet. 

Loch Eiglieach (see Plate XVIII.). Loch Eigheach (or Eaigh), 
about 3 miles from where the river Gaur passes its waters into Loch 
Rannoch, is an expansion, or rather three expansions, of the river 
Gaur, the two western expansions lying on a higher level than the 
eastern one, and hence strong currents run in an easterly direction. 
In high floods the whole area is practically submerged. A large part of 
the loch is covered by reeds, and the bottom is very weedy. The entire 
loch is nearly nine-tenths of a mile in length, with a maximum breadth 
of less than a quarter of a mile, the mean breadth being one-tenth of a 
mile. Its waters cover an area of about 59 J acres, or less than one-tenth 
of a square mile, and it drains directly an area of nearly 14 square 
miles, but since it receives the outflow from Lochan Sron Smeur and 
from Lochs Laidon and Ba, &c., its total drainage area is nearly 63 J 
square miles, or 705 times the area of the loch. The loch was surveyed 
on April 21, 1902, about 80 soundings being recorded, the maximum 
depth observed being 28 feet. The surface of the eastern expansion 
was found by levelling to be 818-2 feet above sea-level, and the water 
apparently rises about 3 J feet above its level on the date surveyed. The 
volume of water contained in the loch is estimated at 15,794,000 cubic 
feet, and the mean depth at 6 feet, or 22 per cent, of the maximum 
depth. The eastern expansion is the deepest, the maximum depth of 
28 feet having been found to the west of the island near the east end 
of this expansion ; the north-western expansion has a maximum depth 
of 7 feet observed not far from the outlet, but the majority of the 



68 BATHYMETRICAL SURVEY OF 

soundings run from 2 to 5 feet; the south-western expansion is the 
shallowest, with a maximum depth of 3 feet to the west of the central 
large island (Eilean na Coille), the bottom to the east and south of that 
island being covered by only 1 foot of water. Over 90 per cent, of the 
entire lake-floor is covered by less than 10 feet of water, and less than 
2 per cent, by over 20 feet of water. The surface temperature in the 
eastern expansion at 11 a.m. on April 21, 1902, was 44-2. 

Loch Rannoch (see Plate XIX.). Loch Rannoch, one of the larger 
and more important of the lochs in the Tay basin, was the headquarters 
of the Lake Survey for nearly four months, from March 20 to July 10, 
1902, and during that period a great many soundings, as well as 
observations on the temperature of the water, on the biology, and on the 
rise and fall of the surface of the loch, were taken, all the members of 
the staff taking part in the work. The lake trends in an east-and-west 
direction, and is a lovely sheet of water, the hills on both sides, and the 
woods clothing its shores in many places, adding beauty to the scene. 
The famous Black Wood of Rannoch on the south side is of great 
antiquity. The loch contains many small trout, and is famed for large 
Salmo ferox. It is nearly 9| miles in length, considerably over a mile 
in maximum breadth, the mean breadth being about three-quarters of 
a mile, or about 8 per cent, of the length. Its waters cover an area of 
over 4700 acres, or nearly 7 \ square miles, and it drains directly an area 
of about 130 square miles, but, since it receives the outflow from Loch 
Ericht, Loch Eigheach, Loch Laidon, Loch Ba, &c., its total drainage 
area is about 243| square miles, or 33 times the area of the loch. 

Over eight hundred soundings were taken in Loch Rannoch, the 
maximum depth observed being 440 feet, or 20 feet deeper than the 
maximum depth recorded by Mr. Grant- Wilson during his survey in 
the year 1888, when he took about 320 soundings. The volume of 
water contained in the loch is estimated at about 34,387,131,000 cubic 
feet, or less than a quarter of a cubic mile, and the mean depth at 167| 
feet, or 38 per cent, of the maximum depth. The length of the loch 
is 116 times the maximum depth, and 306 times the mean depth. The 
loch is widest and deepest in the eastern half, narrowing and shallow- 
ing towards the west on approaching the island Eilean nam Faoileag, 
then deepening again to the west of that island. It consists of one 
large main basin, with two subsidiary small basins over 50 feet in 
depth towards the west end, separated from the main basin by the 
shallow water in the neighbourhood of Eilean nam Faoileag. The 
larger of the two subsidiary basins is about three-quarters of a mile in 
length, stretching from south of the island An t-Eilean Fearna, at the 
entrance of the river Ericht, towards the west end of the loch, and the 
maximum depth recorded in it was 84 feet; the smaller basin lies 
between the two islands mentioned and towards the northern shore, 



THE FRESH \\ATKR LOCHS OF SCOTLAND. 



69 



soundings of 52 and 54 feet having been obtained therein. The main 
50-feet basin is about 7| miles in length, occupying the great body of 
the loch east of Eilean nam Faoileag, and covering an area exceeding 

5 square miles. The 100-feet basin is nearly 7 miles in length, extend- 
ing from between the mouths of the Killichonan burn and the Allt 
Camghouran towards the east end of the loch. The 200-feet basin is 

6 miles in length, stretching from within a quarter of a mile from the 




FIG. 20. LOCH RANNOCH. 

(Photograph by Miss M'Pherson.) 



east end to opposite the house Talla Bheith on the northern shore. The 
main 300-feet basin is nearly 4 miles in length, stretching from less 
than half a mile from the east end to opposite Dall on the southern 
shore, and separated from it by an interval of a quarter of a mile is an 
isolated sounding of 304 feet. Within the 300-feet basin the bottom 
sinks in three places along the central axis of the loch below the 400- 
feet line. The easternmost of these three 400-feet basins is the largest 
and deepest, situated about 1 J miles from the east end, about two-thirds 



70 BATHYMETRICAL SURVEY OF 

of a mile in length, and enclosing the maximum depth of the loch (440 
feet); a short distance to the west (opposite Craiganour) is a second 
small basin based upon a sounding of 404 feet ; and three-quarters of a 
mile farther west is the third basin, with a maximum depth of 421 
feet. The area of the lake-floor covered by less than 50 feet of water 
is about 1200 acres (nearly 2 square miles), or 25 per cent, of the total 
area, while the area between the 50-feet and 100-feet lines is about 750 
acres, or 16 per cent., showing a relatively rapid descent beyond the 
50-feet line. The area between the 100- and 200-feet lines is about 
877 acres, or nearly 19 per cent, of the entire area. The area between 
the 200- and 300-feet lines is about 950 acres, or over 20 per cent., 
the area between the 300- and 400-feet lines is about 875 acres, or 18J 
per cent., and that over 400 feet about 65 acres, or nearly 1 J per cent., 
of the total area of the loch. 

On commencing the survey of Loch Rannoch, the height of the 
surface above sea-level was determined from Ordnance Survey bench- 
marks as 668 feet ; the level of the loch fluctuated during the progress 
of the survey, but the soundings have all been reduced to this datum. 
The officers of the Ordnance Survey on July 19, 1860, found the level 
of the loch to be 667 - 5 feet above the sea. 

Temperature Observations. Very many temperature observations 
were taken between March 20 and July 10, 1902. The surface tem- 
peratures need not be discussed in detail ; the lowest reading recorded 
was 37-9 on March 28, and the highest 59-8 on June 23, showing a 
range of 22 in the temperature of the surface water during the period 
of three months. An interesting series of hourly observations on the 
temperature of the air and of the surface water at the pier at Rannoch 
Lodge was taken on June 9. One thermometer was immersed in 3 feet 
of water outside the pier, and another in 1 foot of water inside the pier, 
and they were read simultaneously with an air-thermometer at intervals 
of one hour from 9 a.m. to 10 p.m. The temperature of the air rose 
gradually, though irregularly, from 48 at 11 a.m. to a maximum of 
53 at 4 p.m., falling gradually again to 44'5 at 9 p.m., and 45 at 
10 p.m. The thermometer in 3 feet of water showed a gradual rise in 
the temperature from 51-9 at 9 a.m. to 53 at 11 a.m., then a slight fall 
at noon (52-7) and at 1 p.m. (52'5), the maximum (53- 6) being 
recorded at 2 p.m., falling to 52-9 at 4 p.m., rising to 53-3 at 5 p.m., 
falling gradually to 52'l at 8 p.m., then rising to 52-8 at 9 p.m., and 
53 at 10 p.m. The thermometer in 1 foot of water showed a gradual 
rise in the temperature from 51'4 at 9 a.m. to the maximum of 53- 6 at 
2 p.m., whence it fell gradually to 51'5 at 9 p.m., the reading at 
10 p.m. being 52. The maximum temperature of the water was 
recorded in each case at 2 p.m., while the maximum temperature of the 
air was recorded at 4 p.m., and the temperature of the air was always 
lower than that of the water, except when the air was at its maximum 



THE FRESH -WATER LOCHS OF SCOTLAND. 



71 



pua sa M 

urd 08-9 

50/9/15 



.9 .99 . . .9 . . . .<? .9 



urd g 
50/9/Z 



ra-v 01 

'50/9/i 



00 OOOS 00 



E .9 



50/9/9 



; S 



OSQO : :oo 



rd gi.i 
7-0/S/S5 



.9 .9 



ittuo a^isoddo 
urdfr 

'SO/S/85 



pU8 '189 M 

tu"B ii 
SO/5/85 



71 71 -N 05 OS 



pua -jsa^i 
ord 9 
20/9/8 



50/5/5 



.<^ 

: ii 



uootuayv 

'c 0/5/1 



' -* 



. 9 9 

Z ::: : ^-- 



urd 08- 8 



. x x r . <?i 

MS ':': cc 

-f- ' -i- -r ' ^ 



c c CK 

cc cc *M : : 

- 



uc T*< cc 



go/Wot 







m-de 



t- -^ 

?*% '% 



X .CCC .C 



50^/fl 



pua ^sa^ 
ra-d cT.f- 



OS OS X 



qoouua 
ajtui 



gQ/r/8 



- ~- ? . ~- 

u g : S :2 



pua ^sa A v 

ra'd 08-8 

'50/t/5 



^S ; s : I ; 



J 8 



pua ^sa^ 
TUOJJ sa^uu a^ 
tu-d fr 



. ~ 



pua jsa A 
ra-d oS-8 

o" ?..'.'? 



O C C 



OS OS 



cc cccccccc 



m-d 08-5 
'50/g/OS 



pi i.. a <., u 
50/8/56 



SP 






* M S S 8 



9 8 8 ^ 8 g 



72 BATHYMETRICAL SURVEY OF 

(53 at 4 p.m.), the thermometer in 3 feet of water then reading 52-9, 
while that in 1 foot of water read 53*3. The temperature recorded in 

1 foot of water was lower than that recorded in 3 feet of water in the 
forenoon and late evening, but at noon and 1 p.m. it was higher, at 

2 p.m. and 3 p.m. it was identical, and from 4 p.m. till 8 p.m. it was 
higher, the greatest difference recorded being 1 0> 3 at 9 p.m. (52-8 at 

3 feet, and 51'5 at 1 foot). 

The temperatures taken beneath the surface have been collected 
together and arranged chronologically in the foregoing table, which may 
be useful for future reference and comparison. The great majority of 
them were taken in the small 80 -feet basin towards the west end of the 
loch, while one series was taken near the east end on April 3, and three 
series were taken towards the middle of the loch, opposite Craiganour, 
on May 1, 2, and 23. The table shows well the heating up of the 
water with the advance of summer. The readings taken near the west 
end in March are all below 39 Fahr. that is, below the maximum 
density point, though surface temperatures exceeding 39, and in one or 
two cases exceeding 40, were recorded near the shore during the last 
days of March. On April 2 and subsequently, the temperature was 
above that of maximum density (39'l), but the observations taken near 
the east end 011 April 3 showed that the temperature of the water from 
surface to bottom was just below maximum density point. The water 
in the small western basin had a temperature under 40 up to April 10, 
and was practically uniform from top to bottom, but on April 21 and 
subsequently the temperature rose, and there was a considerable range 
between the temperature of the upper and lower layers. The water in 
the main basin had a temperature of 40 at 200 and 300 feet on May 1 ; 
on May 2 the temperature was 40-2 at 200 feet; and on May 23 it 
was 41-9 at 100 feet. By the beginning of June the water near the 
surface had attained a temperature of 50, and by June 21 that 
temperature extended down to 50 feet, the upper 10 feet having on 
that date a temperature of 52. 

Loch Lyon (see Plate XXI.). Loch Lyon lies at a high elevation 
at the head of Glen Lyon, amid grand and mountainous scenery, its 
waters being carried by the river Lyon into the river Tay a short 
distance above the mouth of Loch Tay; it contains both salmon and 
trout. It trends in a north-east and south-west direction, and is 
extremely simple both in outline and in the conformation of the bottom. 
It is of nearly uniform width, except for a cone of alluvium, brought 
down by the river, on the south-eastern shore. It is about 1| miles in 
length, with a maximum breadth of over a quarter of a mile, the mean 
breadth being over one-fifth of a mile, or 12 per cent, of the length. 
Its waters cover an area of about 236 acres, or over one- third of a square 
mile, and it drains an area of over 10J square miles, an area nearly 



THE F1M-:>U- \\.\TKR LOCHS OF SCOTLAND. 



73 



twenty-nine times greater than that of the loch. Over 100 soundings 
were taken in Loch Lyon, the maximum depth observed being 100 feet. 
The volume of water contained in the loch is estimated at about 
460,750,000 cubic feet, and the mean depth at 45 feet, or 45 per cent, 
of the maximum depth. The length of the loch is 92 times the maximum 
depth, and 205 times the mean depth. As stated, the loch forms a 
simple basin, the bottom sinking gradually on all sides towards the 
deepest part, which is approximately centrally placed. The deep water, 




FIG. 21. LOCH LYON. 

(Photograph by Sir John Murray.) 

however, approaches much closer to the south-west end than to the 
north-east end, where the 25-feet line is distant about a quarter of a 
mile from the shore, probably through silting up of the lake-floor at that 
end. The 25-feet basin is nearly 1 miles in length, the 50-feet basin 
is about 1J miles in length, and the 75-feet basin is about 1J miles in 
length. The area of the lake-floor covered by less than 25 feet of water 
is about 92 acres, or 39 per cent, of the total area of the loch ; the area 
between the 25- and 50-feet contour-lines is about 36 acres, or over 
15 per cent. ; the area between the 50- and 75-feet contours is about 



74 BATH Y METRICAL SURVEY OF 

55 acres, or over 23 per cent. ; and the area over 75 feet in depth is 
about 53 acres, or less than 23 per cent, of the entire area of the loch. 
The comparatively flat-bottomed character of the deep basin is indicated 
by the larger proportion of the bottom covered by water between 50 
and 75 feet in depth, as compared with the proportion covered by water 
between 25 and 50 feet, the average slope being thus considerably steeper 
in depths of 25 to 50 feet than in depths of 50 to 75 feet ; and this latter 
gentler slope is continued into the deeper water over 75 feet in depth, 
as shown by the nearly equal areas on both sides of the 7 5 -feet line. 
The large proportion under 25 feet in depth is due to the considerable 
silted-up area towards the north-east end of the loch already referred to. 
Loch Lyon was surveyed on May 10, 1902. No bench-marks were to be 
seen along the shores, nor on the Ordnance Survey charts, but the 
height of the surface of the loch was estimated as being about 1050 feet 
above the sea. Lines of drift were observed 4 feet above the water, 
which, according to the keeper, was about its normal height at the time 
of the survey ; the water rises suddenly and falls as quickly, and might 
fall perhaps a foot lower than on the date of the survey. Thus a range 
of about 5 feet in the level of the water is indicated. The temperature 
of the surface water on May 10, 1902, when commencing the survey, 
about noon, was 48'7 at the edge of the bank at the north-east end, 
and readings taken along the shore gave 50, 51-8, 52-5, and 58. In 
the afternoon, readings of 47*9 were taken in shallow water towards the 
northern shore, 48'9 near the south-west end, and 46 0> 4 in the centre 
of the loch. These observations show a range of ll-6 in the temperature 
of the surface water throughout the day, viz. from 46-4 to 58. 

Loch Dochart (see Plate XX.). Loch Dochart, situated at the foot 
Ben More amid beautiful scenery, is the westernmost of the lochs 
belonging to the Tay branch of the Tay river-system, being evidently 
an expansion of the river Fillan, which forms the headwaters of this 
branch. It receives the drainage from a considerable tract of country, 
is very shallow, the bottom is very weedy, and there are many reeds, 
especially at the west end. Loch Dochart is nearly two-thirds of A 
mile in length, with a maximum breadth of nearly one-sixth of a mile, 
the mean breadth being over one-tenth of a mile, or 18 per cent, of the 
length. Its waters cover an area of about 46 acres, or nearly one- 
fourteenth of a square mile, and it drains an area of nearly 39 square 
miles, or 555 times the area of the loch. Nearly 70 soundings were 
taken in Loch Dochart, the maximum depth observed being 1 1 feet ; 
but this depth is of very limited extent, only two isolated soundings 
being recorded near the west end of the loch, while by far the greater 
portion of the bottom is covered by less than 5 feet of water. The 
volume of water contained in the loch is. estimated at 10,032,000 cubic 
feet, and the mean depth at 5 feet, or 46 per cent, of the maximum 



THE FRESH- WATER LOCHS OF SCOTLAND. 75 

depth. The length of the loch is 298 times the maximum depth, and 
652 times the mean depth. Loch Dochart was surveyed on April 28, 
1902, and the level of the surface of the water was determined from 
Ordnance Survey bench-mark as being 513 feet above sea-level. The 
temperature of the surface water at 11.30 a.m. on that date was 50 0> 1. 

Loch lubhair (see Plate XX.). Loch lubhair (or Nubhair) receives 
the outflow from Loch Dochart by a river considerably less than half a 
mile in length, so that they may almost be regarded as forming one lake. 
It affords fair trout-fishing, and the scenery round about is very 
beautiful. Loch lubhair is about 1J miles in length, with a maximum 
breadth of about one-third of a mile, the mean breadth being nearly 
one-sixth of a mile, or 12 per cent, of the length. Its waters cover an 
area of about 135 J acres, or over one-fifth of a square mile, and it drains 
directly an area of about 5J square miles; but, since it receives the 
outflow from Loch Dochart, its total drainage area is over 44J square 
miles, or 212 times the area of the loch. Over 100 soundings were taken 
in Loch lubhair, and the maximum depth observed was 65 feet. The 
volume of water contained in the loch is estimated at 147,284,000 cubic 
feet, and the mean depth at 25 feet, or 38 per cent, of the maximum 
depth. The length of the loch is 110 times the maximum depth, and 286 
times the K meaii depth. Loch lubhair trends in a north-east and south- 
west direction, and is rather peculiar in outline, resembling somewhat 
the italic letter /, constricted in the central portion, where a ridge crosses 
the loch with a maximum depth of 36 feet on it. The loch widens and 
deepens on each side of this constriction, the maximum depth of the 
loch having been found in the north-eastern part, where the loch is 
widest, the greatest depth observed in the south-western part being 
49 feet. The 25 -feet basin is a continuous area over a mile in length, 
approaching close to the northern shore, but distant about a quarter 
of a mile from the south-west end. The area of the lake-floor covered 
by less than 25 feet of water is about 72 acres, or 53 per cent, of the 
total area of the loch ; the area between the 25- and 50-feet contours is 
about 59 acres, or 44 per cent., while the area covered by over 50 feet 
of water is about 5 acres, or 3 per cent, of the entire area of the loch. 
Loch lubhair was surveyed at the same time as Loch Dochart, on April 
28, 1902, the level of its surface being a foot lower than that of Loch 
Dochart, viz. 512 feet above the level of the sea. 

Loch Earn (see Plate XXII.). Loch Earn is situated amid lovely 
surroundings, the hills on both sides being clothed with rich woods, and 
splendid mountain scenery bounds the horizon towards the west, while 
on the south Ben Vorlich towers to a height of 3200 feet. It contains 
trout and salmon, and also Salmo ferox. It has been said that the loch 
is 100 fathoms ( = 600 feet) deep in some places, but this is disproved by 



76 BATHYMETRICAL SURVEY OF 

the soundings taken by different surveyors. Mr. Grant- Wilson took 
over 180 soundings in 1888, Sir John Murray and the late Mr. F. P. 
Pullar took about 150 soundings in 1900, and the Lake Survey took 500 
soundings in 1902, but in no case was the depth found to exceed 288 
feet. On the accompanying map only the Lake Survey soundings are 
laid down, and the contour-lines drawn in from them. 

Loch Earn is 6J miles in length, and four-fifths of a mile in maximum 
breadth, the mean breadth being three-fifths of a mile, or 9J per cent, 
of the length. The waters of the loch cover an area of over 2400 
acres, or nearly 4 square miles, and it drains an area of over 54J 




FIG. 22. LOCH EARN. 

(Photograph by J. Parsons, B.Sc.) 

square miles an area fourteen times greater than the area of the 
loch. Five hundred soundings were taken in Loch Earn, the maximum 
depth observed being 287 feet, which agrees very well with the 
maximum recorded by Mr. Grant-Wilson in 1888, viz. 48 fathoms, 
or 288 feet. The volume of water contained in the loch is estimated 
at 14,420,638,000 cubic feet, and the mean depth at 138 feet, or 48 
per cent, of the maximum depth. The length of the loch is 118 times 
the maximum depth, and 245 times the mean depth. 

Loch Earn forms a simple basin, the lake-floor sinking gradually on 
all sides down to the greatest depth, as is well shown by the longitudinal 
and three cross-sections on the map. The 50-feet contour-line follows 



THE FRESH- WATER LOCHS OF SCOTLAND. 77 

approximately the outline of the loch, approaching very close to the 
west end, where between the mouths of the Ogle and Kendrum burns 
a sounding of 57 feet was taken about 300 feet from the shore, giving a 
slope of 1 in 5'3. At the opposite end of the loch the 50-feet contour is 
met with about one-third of a mile from the bridge across the river at 
St. Fillans. The 100-feet basin approaches to within less than a quarter 
of a mile from the west end, and less than half a mile from the east end, 
and is over 5| miles in length; it covers an area of nearly 2J square 
miles. The 200-feet basin is 4J miles in length, stretching from three- 
quarters of a mile from the west end to 1 miles from the east end, and 
covers an area of 1J square miles. The 250-feet basin is nearly 2 miles 
in length, and a quarter of a mile in maximum width, extending from 
1 J miles from the west end to 3 miles from the east end. The maximum 
depth of 287 feet was observed near the centre of the loch, between the 
mouths of the Allt Bhacaidh on the north and the Allt Dhunain on the 
south, about 2| miles from the west end, and 3| miles from the east 
end. The area of the lake-floor covered by less than 100 feet of water 
is about 926 acres, or 38 J per cent, of the total area of the loch ; the 
area between the 100- and 200-feet contour-lines is about 755 acres, or 
3H per cent. ; and the area covered by more than 200 feet of water is 
about 700 acres, or 30 per cent. The flat-bottomed character of the 
loch is indicated by the last-mentioned percentage, which is nearly 
equal to the preceding one, though the interval of depth is only 87 feet 
as compared with the previous interval of 100 feet. The comparatively 
uniform average slope from the shore down to a depth of 100 feet is 
shown by the fact that the areas on each side of the 50-feet line are 
nearly equal, viz. 477 acres (or nearly 20 per cent, of the entire area of 
the loch) between the shore and the 50-feet contour, and 449 acres (or 
nearly 19 per cent.) between the 50- and 100-feet contours. 

Loch Earn was surveyed on May 14 to 19, 1902, and the level of the 
surface of the water \vas determined by levelling from Ordnance Survey 
bench-mark as 317-2 feet above sea-level. This is identical with the 
level determined by the surveyors of the Ordnance Survey on August 
25, 1899. 

Temperature Observations. On May 14, at 3.45 p.m., the tem- 
perature of the surface water near Lochearnhead was 46'l ; at 6 p.m. 
the surface temperature was 44, and at 7 p.m. near the shore 47'2. 
On May 15, at 11.30 a.m., the surface temperature near shore about 
a mile east of Lochearnhead was 44. On May 16, at 10.30 a.m., the 
surface temperature at the St. Fillans end of the loch was 44-l, and 
at 1-30 p.m. it was 44. On May 17, at 5 p.m., the surface temperature 
off Dalkenneth over the deepest part of the loch was 43'8. The range 
observed in the temperature of the surface water during those four 
days was thus 3-4, from 43 0< 8 to 47-2, the range in the air temperature 
during the same period being 7-5, from 40 0> 5 to 48. 



78 BATHYMETRICAL SURVEY OF 

A series of temperatures beneath the surface was taken in the deepest 
part of the loch on May 17, at 5 p.m., with the following results : 

Surface 43'8 Fahr. 

5 feet 43 -5 

10 43 -4 



20 

30 

50 

100 

125 

150 

200 

250 



43 -3 
43 2 
43 -2 
43 -1 
42 3 
42 -1 
42 -0 
41 -5 



This series shows a range of 2'3 between the temperature at the 
surface and that at 250 feet, the greatest fall being one of 0'8 between 
100 and 125 feet. 

Loch Tummel (see Plate XXIII.). Loch Tummel is situated amid 
beautiful scenery, rock, wood, and water being combined in such a way 
as to present pictures of rare loveliness, the crests of Farragon, Meall 
Tarruinn Chon, and Schiehallion rising to great heights to the south 
and south-west. It contains large trout and a great many pike. Loch 
Tummel is two and three-quarter miles in length, with a maximum 
breadth of half a mile, the mean breadth being a little over one-third 
of a mile, or 13 per cent, of the length. Its waters cover an area of 
630 acres, or rather less than one square mile. It drains directly an 
area of 62J square miles, but since it receives the outflow from Lochs 
Rannoch, Laidon, Ba, &c., its total drainage-area is about 306 square 
miles, or 312 times the area of the loch. Nearly 300 soundings were 
taken in Loch Tummel, the maximum depth observed being 128 feet, or 
4 feet more than the maximum depth recorded by Mr. Grant- Wilson, 
who took 123 soundings in 1888. The volume of water contained in the 
loch is estimated at 1,316,635,000 cubic feet, and the mean depth at 
48 feet, or 37 \ per cent, of the maximum depth. The length of the 
loch is 113 times the maximum depth, and 302 times the mean depth. 
The floor of Loch Tummel is irregular, falling into three deep basins 
separated by two ridges, the maximum depth on the westerly ridge 
being 52 feet, and the maximum depth on the easterly ridge being 56 
feet. The deepest of the three basins is situated near the west end of the 
loch, the maximum depth of 128 feet occupying a central position in this 
basin, but a short distance to the south a sounding of 74 feet is recorded 
in close proximity to a sounding of 127 feet. The 100-feet contour-line 
in this western basin is almost circular and nearly one-third of a mile in 
diameter ; about one-fifth of a mile to the east is an isolated sounding 
of 102 feet, surrounded by shallower water. The central 100-feet basin 
is oblong in outline and nearly half a mile in length, the maximum 



THE FRESH- WATER LOCHS OF SCOTLAND. 



79 



depth of 119 feet having been observed towards the eastern end of the 
basin. The eastern basin just falls short of attaining a depth of 100 
feet, the maximum observed being 99 feet; the 75-feet contour is 
approximately oblong in outline and nearly one-third of a mile in 
length. The 50-feet basin is a continuous area stretching from about a 
quarter of a mile from the west end to within 100 yards from the east 
end of the loch, and is nearly two and a half miles in length. 

The area of the lake-floor covered by less than 50 feet of water is 
about 352 acres, or 56 per cent, of the entire area of the loch; the area 
covered by water between 50 and 100 feet in depth is about 217 acres, 





FIG. 23. LOCH TUMMEL. 

(Photograph by J. Parsons, B.Sc.) 



or 34^ per cent. ; and that covered by more than 100 feet of water is 
about 60 acres, or 9J per cent, of the total area of the loch. 

Loch Tummel was surveyed 011 April 23 and 24, 1902, the level of 
the surface of the water being found, by levelling from Ordnance Survey 
bench-mark, to be 454-5 feet above the sea. When levelled by the 
surveyors of the Ordnance Survey on June 26, 1860, the surface of the 
water was found to be 453'3 feet above sea-level. 

Temperature Observations. The temperature of the surface water of 
Loch Tummel at 1.30 p.m. on April 23, 1902, was 43'2 Fahr. ; at 
9.45 a.m. on the next day (April 24) the surface temperature was 45'0, 
and at 1 p.m. in the centre of the loch the surface temperature was 






80 BATHYMETRICAL SURVEY OF 

43-5. A series of temperatures was taken below the surface at 1 p.m. 
on April 24, 1902, in 102 feet of water, with the following results: 

Surface 43%5 Fahr. 

5 feet 43 v> ,, 

10 43 '4 

20 43 -2 

50 43-0 

70 42-6 

100 42-4 

showing a gradual decrease of temperature from surface to bottom, the 
range of temperature being 1 0> 1 in the 100 feet of water. 

Loch Tay (see Plates XXIV. and XXV.). Loch Tay is one of the 
largest of the Scottish fresh-water lochs, unsurpassed in the beauty of 
its surroundings, and well known to anglers on account of its salmon 
fishings, which are among the best in Scotland. It is also a good trout- 
fishing loch, having been much improved within recent years by being 
stocked with Loch Leven trout. The scenery around the loch is very 
fine grand and wild towards the south-west end, with the mighty Ben 
Lawers rising from its northern shores about half-way down the loch, 
becoming more sylvan in character towards the north-east end, a 
splendid view presenting itself to the eyes of a spectator from Kenmore 
Bridge (see Fig. 24). 

Loch Tay is the largest loch in the basin of the river Tay, though 
Loch Ericht is a very formidable rival for this distinction, as will be 
seen from the following comparison : 





Loch Tay. 


Loch Ericht. 


Length... 


14 '55 miles. 


14'5 miles. 


Maximum breadth ... 


1 -07 miles. 


1 -0 mile. 


Mean breadth... 


070 mile. 0'5 mile. 


Superficial area ... | 10'19 square miles. 
Maximum depth ... 508 feet. 


7 '21 square miles. 
512 feet. 


Mean depth 199 076 feet. 189 "201 feet. 


Volume of water 


56,550 million cub. ft. 


38,027 million cub. ft. 



This comparison shows that the maximum depth observed in Loch 
Ericht slightly exceeds that observed in Loch Tay, but in all other 
respects Loch Tay has the advantage, though as regards length and 
maximum breadth the two lochs are almost identical. 

Loch Tay is over 14J miles in length, and over one mile in maximum 
breadth, the mean breadth being nearly three-quarters of a mile, or 
nearly 5 per cent, of the length. Its waters cover an area of over 6500 
acres, or over 10 square miles, and it drains directly an area of about 
187J square miles, but since it receives the outflow from Lochs Dochart 
and lubhair, its total drainage-area is over 232 square miles, or nearly 



THE FRESH- WATER LOCHS OF SCOTLAND. 81 

23 times the area of the loch. Nearly 1000 soundings were taken 
in Loch Tay, and the maximum depth observed was 508 feet. The 
maximum depth recorded by Mr. Grant-Wilson in 1888, when he took 
415 soundings in Loch Tay, was 85 fathoms, or 510 feet. The volume 
of water contained in the loch is estimated at 56,549,745,000 cubic feet, 
or over one-third of a cubic mile, and the mean cTepth at 199 feet, or 39 
per cent, of the maximum depth. The length of the loch is 151 times 
the maximum depth, and 386 times the mean depth. 

Loch. Tay trends in a north-east and south-west direction, being 
slightly sinuous in outline, somewhat like the italic letter/, as was noted 





FIG. 24. LOCH TAY. FKOM KKNMOUK BRIDGE. 

(Photograph by T. N. Johnton, M.B.. C.M., F.R.S.E.) 



in the case of Loch lubhair, which flows into it. It is extremely simple 
in conformation, the bottom sloping gradually, without any pronounced 
irregularities, on all sides down to the deepest part, as is well shown 
on the longitudinal and cross sections on the map. The 50-feet basin 
approaches to within less than 400 feet from the south-west end and less 
than 800 feet from the north-east end, and is 14J miles in length. The 
slope of the bottom is thus steeper at the south-west end than at the 
north-east end. In the former position a sounding of 65 feet was taken 
about 750 feet from shore, giving a gradient of 1 in 11J, and in the 
latter position a sounding of 80 feet was taken about 1075 feet from 
shore, giving a gradient of 1 in 13J. The 100-feet basin extends from 

G 



82 BATHYMETRICAL SURVEY OF 

about a quarter of a mile from the south-west end to about one-third of 
a mile from the north-east end, and is very nearly 14 miles in length. 
The 200-feet basin stretches from about 1| miles from the north-east end 
to about 2i miles from the south-west end, and is about 11 miles in 
length. The main 300-feet basin approaches to within less than two 
miles from the north-east end, and is over 7| miles in length; it is 
separated, by a slight shoaling of the bottom over an interval of about 
a mile, from a small subsidiary 300-feet basin (based upon soundings of 
301 and 305 feet), which is over half a mile in length. The 400-feet 
basin is over 3J miles in length, lying in the northern half of the loch, 
and approaching to about 3| miles from the north-east end. The 
deepest part of the loch lies between Skiag on the south-eastern shore 
and Cragganruar on the north-western shore, about 5J miles from the 
north-east end of the loch, or about 6 miles by road from Kenmore, 
where there is a small basin over 500 feet in depth, two soundings of 
508 feet being recorded about midway between the two shores. 

The area of the lake-floor covered by less than 100 feet of water is 
estimated at about 1972 acres (over 3 square miles), or over 30 per cent, 
of the total area of the loch ; the area between the 100-feet and 200-feet 
contour-lines is about 1532 acres (nearly 2J square miles), or 23J per 
cent. ; the area between the 200-feet and 300-feet contours is about 
1390 acres (over 2 square miles), or over 21 per cent. ; the area between 
the 300-feet and 400-feet contours is about 1017 acres (over 1J square 
miles), or 15J per cent. ; the area between the 400-feet and 500-feet 
contours is over 600 acres (rather less than one square mile), or over 
9 per cent. ; while the area covered by more than 500 feet of water is 
about 9 acres, or a small fraction of 1 per cent, of the entire area of the 
loch. These gradually decreasing areas between the contour-lines drawn 
in at intervals of 100 feet indicate that the average slope of the bottom 
becomes steeper and steeper on proceeding from the shore out into deep 
water; this is also clearly shown by a comparison of the two shallow 
zones on both sides of the 50-feet contour-line, the area between the 
shore and the 50-feet line being about 1161 acres, while the area 
between the 50-feet and 100-feet lines is about 811 acres, or respectively 
about 18 and 12J per cent, of the total area of the loch. The slope of 
the bottom of the loch is shown on the natural scale and exaggerated 
five times on the longitudinal and cross sections on the map. 

Loch Tay was surveyed on April 29 to May 7, 1902, and the level 
of the surface of the water was determined by levelling from bench- 
marks as being 349-1 feet above the sea. The officers of the Ordnance 
Survey found the level to be 347-9 feet above the sea on August 12, 
1899. 

Temperature Observations. Many surface temperatures were taken 
during the progress of the survey from April 29 to May 7, 1902, the 
readings varying from 41-8 Fahr. to 47-5 a range of 5-7. The higher 



THE FRESH-WATER LOCHS OF SCOTLAND. 



83 



readings, as a rule, were taken near shore, and the lower readings 
towards the centre of the loch over deep water. When visited on May 
28, 1903, the surface temperature at noon, about a mile from Kenmore, 
was found to be 49'3. 

Two serial temperatures were taken beneath the surface in May, 
1902, and one series in May, 1903, as given in the following table : 



Depth (feet). 


May 1, 1902. 
Off Ardeonaig. 


May 6, 1902. 
Between Lawers and 
Fearnan, 4 p.m. 


May 28, 1903. 
1 mile west of Kenmore, 
noon. 





43-8 


42-0 


49-3 


3 






47-0 


5 


43 ! 2 


42<) 


44-5 


10 


43-2 


41-9 


440 


20 


420 


41-9 




25 






43-1 


30 


41 * 


41-8 




50 


41-7 


41-8 


42-9 


100 


41-2 


41-7 


42-5 


150 


41O 






200 


40-8 


41 ^ 




_>.-* i 


40-5 


... 




300 


40-3 


41-0 




350 


... 


41-0 








It will be seen that on May 1, 1902, the temperature of the water down 
to 30 feet was higher than on May 6, 1902, while from 50 feet down- 
wards it was lower. The range of temperature between the surface and 
a depth of 300 feet on May 1 was 3-5 (from 40-3 to 43-8), while on 
May 6 it was only 1 (from 41 to 42). On May 28, 1903, the tem- 
perature of the water was found to be considerably higher from the 
surface down to a depth of 100 feet than was observed in the previous 
May, the range of temperature in the upper 100 feet of water being 6 0- 8 
(from 42-5 to 49-3). 



Loch Derculich (see Plate XXVI.). Loch Derculich, situated in 
Strathtay amid beautiful scenery, affords good fishing, but is strictly 
preserved; it flows by the Derculich burn into the river Tay to the 
north-east of Aberfeldy. It is surrounded by low rounded hills covered 
with heather, and there are few conspicuous boulders, but many small 
ones. To the north are high, steep hills (Farragon, &c.), with grey 
screes. The knoll forming the point at the boathouse on the south- 
eastern shore is high and planted with trees. The burn flows out of the 
loch by an artificial dam and sluice, which was open on the date of the 
survey, and the water in the loch was very low, a long gravelly point 
(not shown on the Ordnance Survey chart) appearing, and the island to 
the north was nearly, while the island to the south was quite, joined 
to the shore. Loch Derculich (pronounced Der'clich) is over half a mile 



84 BATHYMETRICAL SURVEY OF 

in length from north to south, and also in maximum breadth from east 
to west, the mean breadth being over a quarter of a mile, or 45 per cent. 
of the length. Its waters cover an area of over 100 acres, or about 
one-sixth of a square mile, and it drains an area ten times greater 
over 1J square miles. About 60 soundings were taken, the maximum 
depth observed being 70 feet. The volume of water is estimated at 
108,333,000 cubic feet, and the mean depth at nearly 25 feet, or 35 per 
cent, of the maximum depth. The length of the loch is 44 times the 
maximum depth and 126 times the mean depth. A ridge crosses the 
loch at the narrowest part near the middle, the greatest depth on which 
is 34 feet. On both sides of this ridge the water deepens, the maximum 
depth in the southern basin being 45 feet, while the main deep basin 
lies to the north of the ridge, the maximum depth of the loch (70 feet) 
having been found less than a quarter of a mile from the north-eastern 
angle of the loch, where there is a small 50-feet basin about one-tenth of 
a mile in length; a short distance to the north-east is an isolated 
sounding of 50 feet, comparatively close to the north-east shore, 
separated from the 50-feet basin by a sounding of 38 feet. The 25-feet 
basin is a continuous area half a mile in length and over a quarter of a 
mile in breadth. The area of the lake-floor covered by less than 25 feet 
of water is about 53 J acres; that covered by water between 25 and 50 
feet in depth is about 44| acres; while that covered by more than 50 
feet of water is about 2J acres. Loch Derculich was surveyed on May 
27, 1903 ; the elevation above the sea could not be determined. 

Temperature Observations. A series of temperatures was taken 
in the deepest part of the loch at 8 p.m. on May 27, 1903, with the 
following results : 



Surface 


55 -0 Fahr 


10 feet 


51 -0 


15 ,, 


49'0 ,, 


25 


477 ,, 


50 ,, 


47 -1 ,, 


65 


47'0 


70 


47 -0 



The range of temperature from surface to bottom was 8'0, there being 
a fall of 4-0 between the surface and a depth of 10 feet, and a further 
fall of 3-3 between 10 and 25 feet. A comparison of these temperatures 
with those taken in Lochs Daimh and Giorra on the previous day shows 
that the water in Loch Derculich was much warmer from surface to 
bottom than in the two lochs referred to : at the surface the temperature 
was about 5, and at 10 feet 3 to 4 higher ; at the bottom it was 4 
higher than at the bottom of Loch Daimh, and 1 higher than at the 
bottom of Loch Giorra at a much less depth. 

. 

Loch Scoly (see Plate XXVI.). Loch Scoly, a small hill loch in 



THE FRESH- WATER LOCHS OF SCOTLAND. 85 

Strathtay, lying to the north-east of Loch Kennard and west of Loch 
Skiach, and flowing by the Balnaguard burn into the river Tay shortly 
before its junction with the river Tummel, is over a quarter of a mile in 
length, with a maximum breadth of about one-eighth of a mile, the 
mean breadth being about one-sixteenth of a mile or 21 per cent, of the 
length. Its waters cover an area of about 11 J acres, and it drains an 
area 13 times greater, or about a quarter of a square mile. Twenty- 
five soundings were taken, the maximum depth observed being 12 feet. 
The volume of water is estimated at 2,888,000 cubic feet, and the mean 
depth at nearly 5| feet, or 48 per cent, of the maximum depth. The 
length of the loch is 123 times the maximum depth, and 258 times 
the mean depth. The loch forms a simple basin; the deeper water is 
found towards the southern end, the three soundings exceeding 10 feet 
being centrally placed in the southern half of the loch. Only three 
soundings were taken under 5 feet close to the shore, so that the slope 
of the bottom is on the whole moderately steep. The area of the lake- 
floor covered by less than 10 feet of water is over 10 acres, or 88 
per cent, of the total area of the loch, and only a small proportion of this 
area is covered by less than 5 feet of water. Loch Scoly was surveyed 
on May 29, 1903. The temperature of the surface water was 63-0 
Fahr., and a reading at 5 feet gave the same result, while a reading at 
10 feet gave 56 0> a fall of 7'0 in the temperature of the water at 
10 feet as compared with that at 5 feet. 

Loch Ordie (see Plate XXVI.). Loch Ordie is a very pretty loch 
situated amid grouse-moors to the east of the river Tay, and surrounded 
by wooded hills; it is a good trouting loch, but strictly preserved. It 
trends in an east-and-west direction, being widest towards the west end 
and narrowing somewhat towards the east end. It is nearly two-thirds 
of a mile in length, and nearly half a mile in maximum breadth, the 
mean breadth being over a quarter of a mile, or 44 per cent, of the 
length. Its waters cover an area of about 116 acres, or nearly one-fifth 
of a square mile, and it drains an area nearly 24 times greater over 
4 square miles. Sixty-five soundings were taken, the maximum depth 
observed being 69 feet. The volume of water is estimated at 133,110,000 
cubic feet, and the mean depth at 26J feet, or 38 per cent, of the 
maximum depth. The length of the loch is 49 times the maximum 
depth, and 128 times the mean depth. Loch Ordie is extremely simple 
in conformation, the bottom sinking gradually on all sides down to the 
greatest depth, which is approximately centrally placed, though rather 
nearer the west than the east end. The 25-feet basin is about two-fifths 
of a mile in length and over a quarter of a mile in maximum width, 
while the 50-feet basin is about a quarter of a mile in length and one- 
seventh of a mile in maximum width. The area of the lake-floor 
covered by less than 25 feet of water is about 66 acres, or 57 per cent. 



86 BATHYMETRICAL SURVEY OF 

of the total area of the loch; that covered by water between 25 and 
50 feet in depth is about 34 acres, or 29 per cent. ; while that covered by 
over 50 feet of water is about 16 acres, or 14 per cent, of the entire area 
of the loch. Loch Ordie was surveyed on June 3, 1903, and the level of 
the surface of the water was determined by levelling from bench-mark 
as being 946'3 feet above the sea. 

Temperature Observations. Serial temperatures taken in the deepest 
part of the loch gave the following results : 

Surface 57'6 Fahr. 

10 feet 55'3 

15 ,, 49'5 

25 ,, 47'l 

50 45 7 

68 45-4 

The range of temperature from surface to bottom was 12 0> 2, there being 
a fall of 5-8 between 10 and 15 feet. 

Loch na Craige (see Plate XXVI.). Loch na Craige (or na-Craig), 
one of the best trout lochs in the district, is situated in Strathtay about 
3 miles to the south-east of Aberfeldy, and flows into the river Bran by 
the Cochill burn, which also receives the outflow from Loch Hoil. It is 
surrounded by low, heather-clad hills covered with stony debris. It is 
nearly half a mile in length, nearly one-eighth of a mile in maximum 
breadth, the mean breadth being about one-twelfth of a mile, or 16 per 
cent, of the length. The waters of the loch cover an area of about 24 
acres, and it drains an area fourteen times greater, or more than half a 
square mile. Nearly 30 soundings were taken, the maximum depth 
observed being 13 feet. The volume of water is estimated at 7,871,000 
cubic feet, and the mean depth at nearly 1\ feet, or 57 per cent, of the 
maximum depth. The length of the loch is 195 times the maximum 
depth, and 342 times the mean depth. Loch na Craige is a long, 
narrow depression trending in a north- west and south-east direction, 
or nearly north and south. It forms a simple basin, the deep water 
running along the centre of the loch, the area covered by more than 10 
feet of water being over one-third of a mile in length, but it is rather 
curious to note that the maximum depth of 13 feet was found at the 
extreme southern end of the 10-feet basin and comparatively very close 
to the southern shore. The slope of the bottom is thus pretty steep 
here, and in other places the slope is steep ; for instance, two soundings 
of 11 feet were taken about 60 feet from shore, one off the western and 
one off the eastern shore, giving a slope of 1 in 5 -5. About 63 per cent, 
of the lake-floor, or about 15J acres, is covered by less than 10 feet of 
water. Loch na Craige was surveyed on May 29, 1903; the elevation 
of the surface of the water was determined by levelling from bench- 
mark as being 1297-3 feet above the sea. 



THE FRESH- WATER LOCHS OF SCOTLAND. 87 

Temperature Observations. Temperatures were taken in the deepest 
part of the loch, with the following results : 

Surface ..................... l30-OFahr. 

.5 feet ... ............. . ... 60-0 



Loch Kennard (see Plate XXVI.). Loch Kennard, a good fishing 
loch abounding with small trout, is situated in Strathtay, and flows 
into the river Bran by the Ballinloan burn. Its shores are nearly all 
wooded, and where not planted with trees the low hills are covered 
with heather. It is peculiar in outline, somewhat resembling that of a 
young mushroom, the stem pointing west and the apex of the crown 
pointing north-east. It is over two-thirds of a mile in length, and over 
one-third of a mile in maximum breadth, the mean breadth being over 
one-sixth of a mile, or 26 per cent, of the length. Its waters cover an 
area of about 77 acres, or nearly one-eighth of a square mile, and it 
drains an area seven times greater, or nearly nine-tenths of a square 
mile. Nearly 50 soundings were taken, the maximum depth observed 
being 72 feet. The volume of water is estimated at 108,439,000 cubic 
feet, and the mean depth at 32J feet, or 45 per cent, of the maximum 
depth. The length of the loch is 50 times the maximum depth and 111 
times the mean depth Loch Kennard forms a simple basin, with here 
an'd there minor undulations of the bottom. The deepest water (72 feet) 
is found in the centre of the widest part of the loch, to the east of the 
constriction in its outline ; in the middle of this constriction a depth of 
70 feet was found, but immediately to the west the bottom rises to 50 
feet beneath the surface, and falls again further west to a depth of 
63 feet. The 25-feet basin is half a mile in length and over a quarter 
of a mile in maximum width, while the 50-feet basin is over one-third 
of a mile in length. The area of the lake-floor covered by less than 
25 feet of water is nearly 30 acres, or 38 per cent, of the entire area of 
the loch; that covered by water between 25 and 50 feet in depth is 
about 33 acres, or 43 per cent. ; while that covered by more than 50 
feet of water is over 14 acres, or 19 per cent, of the total area of the 
loch. These figures show that the average slope is steeper between the 
shore and the 25-feet contour-line than between the 25-feet and 50-feet 
contours. Loch Kennard was surveyed on May 29, 1903 ; the elevation 
of the surface of the water above the sea was not determined. 

Temperature Observations. Temperatures were taken in the deepest 
part of the loch, with the following results : 

Surface ..................... 56'7 Fahr. 

ofeet .................... 51-0 ,, 

10 ................... 48-3 

2.-> ,, ..................... 46'0 

.->n ,, .................... 45-5 

72 . 45 3 



88 BATHYMETRICAL SURVEY OF 

The range in the temperature of the water from surface to bottom was 
thus ll-4, the fall of temperature between the surface and a depth of 
5 feet amounting to 5-7, that between 5 and 10 feet amounting to 2 0> 7, 
and that between 10 and 25 feet to 2-3. A comparison of these 
temperatures with those taken in Loch Derculich two days previously 
shows that the temperature of the whole body of water in Loch Kennard 
was lower than that in Loch Derculich (except at the surface which 
may be due to the fact that the observations in Loch Kennard were 
made in the early afternoon, while those in Loch Derculich were taken 
in the late evening). 

Loch Skiach (see Plate XXVI.). Loch Skiach, situated in Strath- 
tay, containing large trout as well as pike, flows into Little Loch Skiach 
(which was not sounded) by a short burn with a slight fall, and thence 
by the Pitleoch burn into the Ballinloan burn shortly before it joins 
the river Bran. It is surrounded by low, rounded, heather-clad hills 
with scattered boulders, and the shores are of clean shingle with 
boulders. It is very irregular in outline, the longer axis being nearly 
north and south, and the bottom is also irregular. It is over three- 
quarters of a mile in length, and nearly half a mile in maximum 
breadth, the mean breadth being nearly one-fifth of a mile, or 25 per 
cent, of the length. Its waters cover an area of about 98 acres, or 
over one-seventh of a square mile, and it drains an area six times 
greater an area of nearly one square mile. Eighty-five soundings were 
taken in Loch Skiach, the maximum depth observed being 55 feet. 
The volume of water is estimated at 77,185,000 cubic feet, and the mean 
depth at 18 feet, or 33 per cent, of the maximum depth. The length of 
the loch is 75 times the maximum depth, and 228 times the mean depth. 
Near the middle a ridge crosses the loch from south-east to north-west, 
on which the depth is less than 20 feet; this ridge separates the two 
deep basins, of which the southerly one is the deeper, the maximum 
depth of 55 feet having been recorded about a quarter of a mile from 
the southern end of the loch, while the greatest depth recorded in the 
northern basin was 45 feet in two places. The two 25-feet basins are 
each under a quarter of a mile in length. Near the middle of the loch 
the slope of the bottom is very steep in places for instance, a sounding 
of 33 feet was taken off the eastern shore at a distance of about 100 feet, 
giving a slope of 1 in 3, and a sounding of 26 feet about the same 
distance off the western shore gives a slope of 1 in 3 -8. The area of the 
lake-floor covered by less than 25 feet of water is about 77 acres, or 79 
per cent, of the total area of the loch; that covered by water between 
25 and 50 feet in depth is about 20 acres, or 20 per cent. ; while that 
covered by more than 50 feet of water is only about 1J acres, or 1 pel- 
cent . Loch Skiach was surveyed on June 12, 1903, and the level of the 
surface of the water was determined by levelling from bench-mark as 
being 1385-7 feet above the sea. 



THE FRESH- WATER LOCHS OF SCOTLAND. 89 

Temperature Observations. The temperature of the surface water on 
commencing the survey at 9 a.m. on June 12, 1903, was 59-0 Fahr. 
Later in the day serial temperatures were taken in the deepest part 
of the loch, with the following results: 

Surface 60 i)Fahr. 

10 feet 59 -0 ,, 

15 ,, 55-3 ,, 

20 49'2 

' 49'0 >. 

45 ,, 48-0 

55 ,, ... ... ... ... ... ... ... 47'5 ,, 

The range in the temperature of the water from surface to bottom was 
thus 12 0> 5 ; between the surface and a depth of 10 feet the fall was only 
1, but between the depths pf 10 and 20 feet the fall of temperature 
amounted to nearly 10 3-7 between 10 and 15 feet, and 6'l between 
15 and 20 feet. These readings are all higher than those taken in Lochs 
Kennard and Derculich about a fortnight earlier in the season. 

Loch Broom (see Plate XXVII.). Loch Broom, a fine trout loch, 
but strictly preserved, lies to the east of the river Tummel, into which 
it flows by the Lochbroom burn to the north of Ballinluig, before the 
river Tummel joins the river Tay. It is nearly three-quarters of a mile 
in length, and over one-third of a mile in maximum breadth, the mean 
breadth being nearly one-fifth of a mile. Its waters cover an area of 
about 86 acres, or over one-eighth of a square mile, and it drains an 
area of 3J square miles an area 26 times greater than the area of the 
loch. Over 60 soundings were taken in Loch Broom, the maximum 
depth observed being 9 feet. The volume of water contained in the loch 
is estimated at 18,813,000 cubic feet, and the mean depth at 5 feet, or 
56 per cent, of the maximum depth. The length of the loch is 422 times 
the maximum depth, and 757 times the mean depth. 

Loch Broom is very shallow, being simply a large bog-hole, or 
depression in the moorland, with shores of yellow sandy debris covered 
by peat, and all heather clad. The outflow is over a dam about 5 feet 
high, so that the greater part of the loch must be artificial. Where the 
depth is less than 5 feet the bog-bean is everywhere seen, and there are 
numerous islets some of peat, others chiefly of bog-bean on several of 
which gulls nest. The deeper water (over 5 feet) lies to the east and 
north of the islets, the maximum depth of 9 feet having been observed 
in several places towards the eastern shore ; along the western shore and 
around the islets the bottom is covered by less than 5 feet of water, but 
at the outflow, where the waters of the loch pass into Lochbroom burn, 
two soundings of 5 feet were taken. The area of the lake-floor covered 
by less than 5 feet of water is about 38 acres, or 44 per cent, of the 
entire area of the loch, while that covered by more than 5 feet of water 



90 BATHYMETRICAL SURVEY OF 

is about 48 acres, or 56 per cent. Loch Broom was surveyed on June 
11, 1903, but the elevation above the sea could not be determined. 
Drift-marks were observed 3 feet above the level of the water on the 
date surveyed. 

The temperature of the surface water on commencing the survey at 
noon on June 11, 1903, was 60'0 Fahr., and two readings in open 
water one at the surface and one at a depth of 8 feet gave in each 
case 60-8. 

Loch Essan (see Plate XXVII.). Loch Essan (or Easain), a hill loch 
lying to the north of Loch Dochart, containing dark-coloured trout of 
rare quality, but strictly preserved, flows by the Allt Essan into the 
river Dochart after it leaves Loch lubhair. It is nearly half a mile in 
length, and over one-fifth of a mile in maximum breadth, the mean 
breadth being about one-ninth of a mile. Its waters cover an area of 
about 32 acres, and it drains an area of over 1J square miles an area 
32 times greater than the area of the loch. Over 40 soundings were 
taken in Loch Essan, the maximum depth observed being 18 feet. The 
volume of water is estimated at 9,664,000 cubic feet, and the mean 
depth at nearly 7 feet, or 38 per cent, of the maximum depth. The 
length of the loch is 135 times the maximum depth, and 356 times the 
mean depth. The loch trends in an east and west direction, and is very 
irregular in outline. The bottom is also irregular, forming three small 
basins with depths exceeding 10 feet, the westernmost being the deepest, 
the maximum depth of 18 feet having been observed about one-sixth of a 
mile from the west end of the loch. To the east of this western deep 
basin, and near the centre of the loch, lies a heap of stones around 
which soundings of 6 feet were taken. A little farther to the east lies 
the central 10-feet basin, based on a sounding of 11 feet. To the east 
of the central basin there is a constriction in the outline of the loch in 
which soundings of 7 and 8 feet were taken, and on approaching the east 
end the loch widens out, and the bottom sinks to form the third (eastern) 
10-feet basin, the maximum depth in which is 16 feet. To the south of 
this eastern basin is a small island, the passage between the island and 
the shore being obstructed by weeds, and weeds are also abundant along 
the northern shore. The area of the lake-floor covered by less than 10 
feet of water is about 26 acres, or 81 per cent, of the total area of the 
loch, while that covered by more than 10 feet of water is about 6 acres, 
or 19 per cent. Loch Essan was surveyed on June 16, 1903, the 
elevation of the surface of the water being estimated at about 1440 feet 
above sea-level. 

Lochan Breaclaich (see Plate XXVII.). Lochan Breaclaich (or 
Loch-an-Breacklaich), a hill loch containing fine trout, flows into Loch 
Tay near its south-west end by the Allt na Breaclaich. It is peculiar 






THE FRESH- WATER LOCHS OF SCOTLAND. 91 

in outline, somewhat resembling the capital letter Y, a promontory of 
land projecting into the loch from the eastern shore opposite the inlet 
on the western shore which leads to the outflow. The length of the loch 
from north-east to south-west in a straight line is about half a mile, but 
a line following the axis of deep water would be considerably over half 
a mile in length. The maximum breadth is about one-third of a mile, 
and the mean breadth about one-seventh of a mile. Its waters cover 
an area of about 43 acres, and it drains an area twenty times greater, 
or about 1J square miles. About 60 soundings were taken in Lochan 
Breaclaich, the maximum depth observed being 41 feet. The volume of 
water is estimated at 26,619,000 cubic feet, and the mean depth at 14 
feet, or 34 per cent, of the maximum depth. The length of the loch is 
64 times the maximum depth, and 187 times the mean depth. The 
bottom of the loch is fairly regular, sinking, to the north and south of 
the promontory referred to, into two basins with depths exceeding 25 
feet, occupying the arms, as it were, of the letter Y, while the shank of 
the letter, leading to the outflow, is occupied by shallower water. Of 
the two deep basins the northern one is the larger and deeper, the 
maximum depth of 41 feet having been found approximately in the 
centre of this basin, but towards the north-western shore, while the 
southern basin is based upon soundings of 32 and 26 feet. The 10-feet 
basin is a continuous area extending from close to the north-eastern end 
to near the south-western end, and occupying the greater portion of the 
loch. The area of the lake-floor covered by less than 10 feet of water is 
over 19 acres, or 45 per cent, of the total area of the loch, while that 
covered by more than 10 feet of water is nearly 24 acres, or 55 per cent. 
Lochan Breaclaich was surveyed on June 16, 1903, but the elevation of 
its surface above the sea could not be determined. 

Temperature Observations. The temperature of the surface water 
on commencing the survey at 2 p.m. on June 16, 1903, was 57 0- Fahr. 
Serial temperatures taken in the deepest part of the loch gave the 
following results : 



Surface 


57 -5 Fahr 


5 feet 


57'5 , 


10 


57 C '4 


t 


15 


51 c -2 


. 


20 , 


49 -3 




40 , 


48 O 


i 



It will be observed that the range of temperature from surface to 
bottom amounted to 9-5, and that the fall of temperature between the 
depths of 10 and 15 feet amounted to 6-2. 

Lochan na Lairige (see Plate XXVII.). Lochan na Lairige lies 
to the west of Ben Lawers and flows into Loch Tay by the Allt a' 
Mhoirneas, which enters the loch nearly opposite the entrance of the 



92 BATHYMETRICAL SURVEY OF 

Allt na Breaclaich. It trends in a north and south direction, and is 
extremely simple in outline and conformation ; it is oblong in outline, 
and of nearly uniform width throughout. It is nearly three-quarters 
of a mile in length, and over one-eighth of a mile in maximum breadth, 
the mean breadth being one-tenth of a mile, or 14 per cent, of the 
length. Its waters cover an area of about 47 J acres, and it drains an 
area 16 times greater, or about 1J square miles. Over 40 soundings 
were taken, the maximum depth observed being 39 feet. The volume of 
water is estimated at 22,682,000 cubic feet, and the mean depth at 11 
feet, or 28 per cent, of the maximum depth. The length of the loch is 
99 times the maximum depth, and 350 times the mean depth. The 
northern portion of the loch is shallow, and water deepening gradually 
on proceeding southwards until the maximum depth is encountered 
about one-eighth of a mile from the southern end, thence the water 
shallows rapidly towards the south end. The 10-feet basin is about half 
a mile in length, extending from near the south end to within one-sixth 
of a mile from the north end. The 2 5 -feet basin is contained in the 
southern half of the loch, and is about a quarter of a mile in length. 
The area of the lake-floor covered by less than 10 feet of water is over 
29 acres, or 62 per cent, of the entire 'area of the loch, while that covered 
by more than 10 feet of water is over 18 acres, or 38 per cent., of which 
8 per cent, exceeds 25 feet in depth. Lochan na Lairige was surveyed 
on June 16, 1903 ; the surface of the water was estimated at about 1595 
feet above the level of the sea. 

Lochs Daimh and Giorra. Lochs Daimh and Giorra, situated in the 
wilds of Glenlyon, amid grand and mountainous scenery, are good 
trouting lochs, but strictly preserved. Loch Daimh flows into Loch 
Giorra by a short river, and the outflow from both lochs is carried into 
the river Lyon by the Allt Conait. To the south, on the flanks of 
Stuchd an Lochain, lies the small Lochan nan Cat, at an elevation of 
over 2000 feet above the sea, which flows into the river between Lochs 
Daimh and Giorra. It being reported that this little lochan was frozen 
over a few days before the date of the survey of Lochs Daimh and 
Giorra, it was visited in the hope of taking soundings through holes in 
the ice, but the ice had disappeared. It was apparently shallow all 
round the shore, except where there are screes from the cliffs, and, if 
at all deep, it must be over a very limited area. The temperature of 
the water was 53-0 Fahr., while a reading taken close under the crags 
beside the snow gave 49- 8. 

Loch Daimh (see Plate XXVII.). Loch Daimh (or Damh) trends 
in an east-and-west direction, being widest and deepest towards the west 
end, narrowing and shallowing towards the east end. It is nearly a 
mile in length, and nearly one-third of a mile in maximum breadth, 
the mean breadth being nearly one-fifth of a mile, or 19 per cent, of 



THE FRESH- WATER LOCHS OF SCOTLAND. 93 

the length. Its waters cover an area of about 111 acres, or over one- 
sixth of a square mile, and it drains an area nearly 30 times greater, 
or over 5 square miles. Nearly 60 soundings were taken, the maximum 
depth observed being 95 feet. The volume of water is estimated at 
189,623,000 cubic feet, and the mean depth at 39 feet, or 41 per cent, 
of the maximum depth. The length of the loch is 53 times the maximum 
depth and 130 times the mean depth. The loch is of simple conforma- 
tion, and, on the whole, comparatively deep, only half a dozen soundings 
under 10 feet being recorded close to the shore. Off the northern shore, 
towards the west end, the slope of the bottom is very steep, soundings 
of 31 feet and 44 feet having been taken about 80 and 100 feet from the 
shore respectively; this is equal to a slope of 1 in 2-3 to 2-6. The 
eastern end, and south-eastern portion of the loch around the island, are 
comparatively shallow. The 25-feet basin is about three-quarters of a 
mile in length, stretching from quite close to the west end to within 
one-sixth of a mile from the east end. The 50-feet basin is nearly half 
a mile in length, and the 75-feet basin, occupying the western half of 
the loch, is over one-third of a mile in length. The maximum depth 
of 95 feet was observed in two places approximately near the centre of 
the wide western portion of the loch. The area of the lake-floor 
covered by less than 25 feet of water is about 50J acres, or over 45 per 
cent, of the total area of the loch ; that covered by water between 25 
and 50 feet in depth is about 21J acres, or over 19 per cent.; that 
covered by water between 50 and 75 feet in depth is about 19 acres, or 
17 per cent. ; and that covered by more than 75 feet of water is about 
20J acres, or over 18 per cent, of the entire area of the loch. The flat- 
bottomed character of the deep western portion of the loch is well 
brought out by a comparison of the last two percentages, while the high 
percentage of the bottom covered by less than 25 feet of water is due to 
the comparatively large shallow area in the south-eastern and eastern 
part of the loch. Loch Daimh was surveyed on May 26, 1903, but the 
level of the surface of the water above the sea could not be determined. 
Temperature Observations. The temperature of the surface water 
on commencing the survey at 9.30 a.m. on May 26, 1903, was 51*0 
Fahr., and a series of temperatures taken in the deepest part of the 
loch gave the following results : 

Surface 50 -3 Fahr. 

10 feet 47-0 

25 44-0 

50 43'5 

90 ,, 43-0 

The range in the temperature of the water from surface to bottom was 
thus 7'3. The fall of temperature from the surface to a depth of 
10 feet amounted to 3-3, and that between the depths of 10 and 25 feet 
amounted to 3-0, and below 25 feet the fall amounted to 1-0. 



94 BATHYMETRICAL SURVEY OF 

Loch Giorra (see Plate XXVII.). Loch Giorra (or Girre) trends 
almost east and west ; there is a slight bend near the middle of the loch, 
the eastern half trending north-west and south-east. It is over four- 
fifths of a mile in length, with a maximum breadth of over a quarter 
of a mile, the mean treadth being about one-sixth of a mile, or 20 per 
cent, of the length. Its waters cover an area of about 88J acres, or 
less than one-seventh of a square mile, and^ it drains directly an area of 
over 5J square miles, but, since it receives the outflow from Loch 
Daimh, its total drainage area is over lOf square miles an area 78 
times greater than the area of the loch. Fifty-five soundings were taken 
in Loch Giorra, the maximum depth observed being 49 feet. The 
volume of water is estimated at 83,686,000 cubic feet, and the mean 
depth at nearly 22 feet, or 44 per cent, of the maximum depth. The 
length of the loch is 88 times the maximum depth, and 200 times the 
mean depth. 

The floor of Loch Giorra is rather irregular. The deepest part is in 
the western half, the maximum depth of 49 feet having been observed 
about one-sixth of a mile from the west end. The 2 5 -feet basin in this 
part of the loch is about two-fifths of a mile in length, and towards the 
east end there is a second 25-feet basin about one-fifth of a mile in 
length, in which the maximum depth is 40 feet. These two basins are 
separated by a remarkable rise of the bottom, on which depths of 15 
and 18 feet were recorded, surrounded 011 all sides by deeper water. The 
area of the lake-floor covered by less than 20 feet of water is nearly 
43 acres, or over 48 per cent, of the total area of the loch ; that covered 
by water between 20 and 40 feet in depth is nearly 38 acres, or about 
42 per cent. ; while that covered by more than 40 feet of water is 
over 8 acres, or over 9 per cent. Loch Giorra was surveyed on the same 
day as Loch Daimh (May 26, 1903) ; its elevation above the sea could 
not be determined. 

Temperature Observations. A series of temperatures taken in the 
deepest part of the loch gave the following results : 

Surface ... 50'OFahr. 

10 feet 48-0 ,, 

25 ,, 46-8 

45 ,, 40 -o ,, 

A comparison of these temperatures with those taken in Loch Daimh 
later in the day shows that, while the surface temperature in each loch 
was nearly identical, the temperature of the water beneath the surface 
was lower in the deeper loch : thus at 10 feet the temperature in Loch 
Daimh was 1-0 lower than in Loch Giorra, at 25 feet it was 2-8 lower, 
and at 50 feet it was 2'5 lower than at 45 feet in Loch Giorra. 

Loch Bhac (see Plate XXVIII,). Loch Bhac (Bhaic, or Vach) lies 
to the north of Loch Tummel, and flows by the Allt Bhaic into the river 



THE FRESH- WATER LOCHS OF SCOTLAND. 95 

Garry between Struan and Blair Atholl. It contains fine trout, but the 
fishing is strictly preserved. It is surrounded by low, heather-clad hills, 
which slope gradually up from the shores of the loch. There are few 
weeds, and the bottom is sandy, or (in parts) gravelly. Loch Bhac 
trends in a north-east and south-west direction, and is extremely simple 
in outline and in conformation. It is over one-third of a mile in 
length, and one-sixth of a mile in maximum breadth, the mean breadth 
being over one-eighth of a mile, or 33 per cent, of the length. Its 
waters cover an area of about 31 acres, or one-twentieth of a square 
mile, and it drains an area thirty-six times greater, or nearly 2 square 
miles. About 30 soundings were taken, the maximum depth observed 
being 42 feet. The volume of water contained in the loch is estimated 
at 22,104,000 cubic feet, and the mean depth at 16J feet, or 39 per cent, 
of the maximum depth. The length of the loch is 48 times the maximum 
depth, and 122 times the mean depth. Loch Bhac forms a simple basin, 
the bottom sloping gradually down on all sides to the deepest part, 
which is approximately centrally placed, but rather nearer to the 
southern end and to the eastern shore, where the slope of the bottom is 
steeper than at the northern end and off the western shore. The area 
of the lake-floor covered by less than 10 feet of water is about 16 acres, 
or 51 per cent, of the entire area of the loch; that covered by water 
between 10 and 25 feet in depth is about 8 acres, or 25 per cent. ; and 
that covered by more than 25 feet of water is about 7 acres, or 24 per 
cent, of the total area of the loch. Loch Bhac was surveyed on July 6, 
1903, but the elevation of its surface above the sea could not be deter- 
mined from bench-mark, though from a spot-level at the north end of 
the loch it is apparently slightly under 1070 feet. The water rises and 
falls very little, the range being probably less than 1 foot. On 'com- 
mencing the survey at 6.15 p.m., the temperature of the surface water 
was 53-0 Fahr., and in the centre of the loch a little later readings at 
the surface, at 25 feet, and at 40 feet gave identical results, 45'0. 

Loch Con (see Plate XXVIII.). Loch Con (Chon, or Choin) lies 
to the east of Loch Garry, and flows by the Allt Choin into Erochy 
water, which joins the river Garry at Struan. It was formerly a good 
trout loch, but now contains many pike, which are supposed to have 
been maliciously introduced. Its gradually sloping shores are heather- 
clad, with few large boulders.* There are trees on the islands and on the 
promontory at the west end. The outflowing burn goes through a large 
flat mass of moraine debris, which extends far down the burn. The loch 
trends in an east and west direction, and is extremely irregular in 
outline, being almost divided into two portions by a narrow constriction 
near the middle. It is nearly a mile in length, and over a quarter of 
a mile in maximum breadth, the mean breadth being over one-tenth of 
a mile, or 11 J per cent, of the length. Its waters cover an area of about 



96 BATHYMETRICAL SURVEY OF 

65 acres, or one-tenth of a square mile, and it drains an area of over 3| 
square miles an area 37 times greater than the area of the loch. Over 
60 soundings were taken, the maximum depth observed being 9 feet. 
The volume of water contained in the loch is estimated at 9,818,000 
cubic feet, and the mean depth at 3J feet, or 39 per cent, of the 
maximum depth. The length of the loch is 550 times the maximum 
depth and 1430 times the mean depth. Loch Con is very shallow, and 
the central constriction cuts it into two basins, the deepest water being 
found near the east end, where two soundings of 9 feet were taken, 
while a sounding of 8 feet was taken in the basin to the north-west of 
the constriction. The area of the lake-floor covered by less than 5 feet 
of water is about 51 acres, or 78 per cent, of the total area of the loch. 
Loch Con was surveyed on July 4, 1903, but the level above the sea 
could not be determined with certainty because of the disparity between 
the spot-levels around the loch. The loch was about its lowest on the 
date of the survey, and drift-marks were observed about 3 feet above the 
water. The temperature of the surface water on commencing the survey 
at 3 p.m. was 54-3 Fahr., and at 5 p.m. readings at the surface and at 
a depth of 8 feet both gave 55 0< 0. 

Loch Tilt (see Plate XXVIII.). Loch Tilt, at the head of the glen 
of that name, consists in reality of two lochs, a broad burn flowing 
from the larger (northern) loch to the smaller loch, which is about one 
foot lower and full of weeds. The larger loch is nearly half -filled with 
weeds (Equisetuni), and the bottom is stony where free from weeds. 
The shore is stony, and the loch is surrounded by an almost flat terrace 
of peat with stones, with high, rounded, heather-clad hills on the west 
side. Loch Tilt is over one-third of a mile in length, and one-fifth of a 
mile in maximum breadth, the mean breadth being about one-thirteenth 
of a mile, or 22 per cent, of the length. Its waters cover an area of 
about 17 acres, and it drains an area twenty-one times greater an 
area of nearly two-thirds of a square mile. Over 20 soundings were 
taken, the maximum depth observed being 5 feet. The volume of water 
is estimated at 1,839,000 cubic feet, and the mean depth at 2J feet, or 
50 per cent, of the maximum depth. Loch Tilt is shallow, the great 
majority of the soundings giving depths of 3 and 4 feet, only two 
soundings of 2 feet and two soundings of 5 feet being recorded. The 
deeper water occurs off the eastern shore, one sounding of 5 feet having 
been taken about 60 feet from that shore, giving a gradient of 1 in 12. 
Weeds are abundant off the south-western shore, and in the northern 
angle of the loch, where there are many large stones in the water. 
Loch Tilt was surveyed on July 9, 1903, and the level of the surface 
was determined, by levelling from bench-mark, as being 1653*5 feet 
above the sea. The water in the loch was low, and drift-marks were 






THE FRESH- WATER LOCHS OF SCOTLAND. 97 

observed about a foot above the water. The surface temperature at 
6 a.m. on the date of the survey was 54'0. 

Loch Moraig (see Plate XXVIII.). Loch Moraig is an artificial 
loch, having been originally an old snipe marsh banked up on the 
south ; it flows by a short stream (the Allt Chluain) into the river Garry, 
between Blair Atholl and Killiecrankie. It is well stocked with fine 
trout, but the fishing is strictly preserved. The surrounding grassy 
hills slope gently up from the loch. It trends in a north and south 
direction, and is very irregular in outline, being widest at the southern 
end, while the northern end is narrow and filled with weeds. It is over 
half a mile in length, and over a quarter of a mile in maximum breadth, 
the mean breadth being over one-tenth of a mile, or 19 per cent, of the 
length. Its waters cover an area of 37 acres, or about one-seventeenth 
of a square mile, and it drains an area of over 2 square miles : an area 
thirty-five times greater than the area of the loch. About 40 soundings 
were taken, the maximum depth observed being 14 feet. The volume of 
water contained in the loch is estimated at 8,921,000 cubic feet, and the 
mean depth at 5J feet, or 40 per cent, of the maximum depth. The 
length of the loch is 207 times the maximum depth, and 524 times the 
mean depth. Loch Moraig is on the whole shallow, only four soundings 
exceeding 10 feet being recorded. The deepest water was found at the 
southern end near the outflow, the maximum depth of 14 feet being 
taken about 60 feet from the southern shore, giving a slope of 1 in 4-3 ; 
in this place soundings of 12 and 11 feet were also taken, and in the 
northern half of the loch an isolated sounding of 10 feet was recorded. 
The area of the lake-floor covered by less than 10 feet of water is about 
34 acres, or 92 per cent, of the total area of the loch. Loch Moraig was 
surveyed on July 7, 1903, but the elevation above the sea was not 
determined; from spot-levels the elevation is probably about 1105 feet. 
On the date of the survey the water in the loch was high owing to 
recent rains, and the embankment was only a foot or two above the 
loch, so that the water could rise only a very little higher. 

Temperature Observations. On commencing the survey at 11 a.m., 
the temperature of the surface water was 52'0 Fahr. Temperatures 
taken in the deepest part of the loch gave the following results : 

Surface 52 -2 Fahr. 

8 feet 51-8 

14 51'4 

Loch Loch (see Plate XXVIII.). Loch Loch, a good trout loch, 
and containing char also, is situated amid wild mountainous scenery, 
the hills on both sides being very steep Ben-y-gloe on the west, and 
the precipitous crags of Craig an Loch on the east. Mounds of gravelly 
morainic debris occupy the greater part of both shores, forming the 

H 



98 BATHYMETRICAL SURVEY OF 

prominent points. It flows northward by the An Lochain into the river 
Tilt, which also receives the waters from Loch Tilt at the head of the 
glen. It trends almost due north and south, and is a long narrow loch, 
or rather two lochs, there being a very narrow constriction near the 
middle dividing it into two portions ; the two lochs were quite distinct 
on the date of the survey, with a difference in level of about half a foot. 
It is about 1 miles in length, the southern portion being half a mile, 
and the northern portion three-quarters of a mile in length, and about 
one-sixth of a mile in maximum breadth, the mean breadth being about 
one-tenth of a mile, or 8 per cent, of the length. Its waters cover an 
area of about 81 acres, or one-eighth of a square mile, and it drains an 
area of about 2 J square miles, an area nineteen times greater than that 
of the loch. One hundred soundings were taken, the maximum depth 
observed being 81 feet. The volume of water contained in the loch is 
estimated at 103,197,000 cubic feet, and the mean depth at over 29 feet, 
or 36 per cent, of the maximum depth. The length of the loch is 80 
times the maximum depth and 222 times the mean depth. Loch Loch 
is peculiar in outline and in conformation. Besides the principal central 
constriction, which cuts the loch into two approximate Jialves, there 
are three minor constrictions, each accompanied by a shoaling of the 
bottom; the most important of these divides the southern half of the 
loch into two basins, the more southerly of which has a maximum 
depth of 40 feet, while the maximum depth in the second basin is 53 
feet. But the greatest depth of the loch is found in the northern half, 
about one-fifth of a mile above the central constriction, where the loch 
is widest. Here the maximum depth of the loch (81 feet) occurs, 
approximately centrally placed, but rather nearer the western than the 
eastern shore, and here the slope of the bottom is very steep, a sounding 
of 80 feet having been taken about 200 feet off the western shore, giving 
a gradient of 1 in 2J, while a sounding of 75 feet was taken about the 
same distance off the eastern shore. From the position of maximum 
depth the water shoals, and the loch narrows, gradually towards the 
northern end. The area of the lake-floor covered by less than 25 feet 
of water is about 45 acres, or 55 per cent, of the total area of the loch ; 
that covered by water between 25 and 50 feet in depth is about 21 
acres, or 26 per cent. ; that covered by water between 50 and 75 feet in 
depth is about 10 acres, or 13 per cent., and that covered by more than 
75 feet of water is about 5 acres, or 6 per cent, of the entire area of the 
loch. Loch Loch was surveyed on July 9, 1903, but the elevation above 
the sea could not be determined from bench-mark ; from a spot-level of 
1480 feet a short distance up the inflowing burn, the elevation is 
probably about 1450 feet. There was no evidence that the loch rises 
more than a foot higher than on the date surveyed. 

Temperature Observations. Serial temperatures were taken in the 
two halves of the loch : (1) in 40 feet of water near the southern end 



THE FRESH-WATER LOCHS OF SCOTLAND. 



99 



of the loch, and (2) in the deepest part of the northern portion of the 
loch, with the following results: 





Southern half. 


Northern half. 


Surface 










52-5 




51-7 


5 feet 








517 




10 










51-2 




20 








. 


51-2 




25 












50-8 


40 










51-0 




50 








50-0 


75 








49-5 



These observations indicate a lower temperature throughout the deeper 
water in the northern half, as compared with the shallower water in 
the southern half of the loch ; the range of temperature in the 40 feet 
of water near the southern end amounts to l-5, as compared with a 
range of 2-2 in the 75 feet of water in the northern portion of the loch. 

Loch nan Eun (see Plate XXVIII.). Loch nan Eun (or na-Nean), 
a beautiful but lonely little loch at the head of Glen Taitneach (or the 
Pleasant Glen) amid extremely wild scenery, is well stocked with trout 
said to be as fine as in any river or loch in Scotland. It flows into the 
Shee water at the head of Glenshee. It is surrounded by high hills with 
rounded tops, and grey with bare rock or screes. Its shores are peaty, 
with many small stones and a few large ones. Loch nan Eun trends in 
a north-east and south-west direction, and is very peculiar in outline, 
consisting of a subcircular body with a broad arm, in which are two 
comparatively large islands, and a short narrow arm extending towards 
the north-east. It is nearly half a mile in length, and nearly a quarter 
of a mile in maximum breadth, the mean breadth being one-eighth of a 
mile, or 28 per cent, of the length. Its waters cover an area of about 
37 acres, and it drains an area five times greater, or about one-third of 
a square mile. Over 50 soundings were taken, the maximum depth 
observed being 50 feet. The volume of water is estimated at about 
34,459,000 cubic feet, and the mean depth at 21 J feet, or 43 per cent, 
of the maximum depth. The length of the loch is 47 times the maximum 
depth, and 110 times the mean depth. Loch nan Eun is comparatively 
deep, considering its superficial area, and the soundings reveal some 
interesting irregularities of the bottom ; for instance, the line of 
soundings taken across the widest and deepest part of the loch from 
west to east shows that the bottom sinks gradually off the western shore 
to 15, then 46, and then 50 feet (the maximum depth of the loch, 
situated about 300 feet from the western shore), thence rising rapidly 
to 29 feet, sinking gradually to 32 and 33 feet, then rising sharply 
again to 12 feet, and finally sinking to 26 feet at a distance of about 50 



100 BATHYMETRICAL SURVEY OF 

feet from the eastern shore. The last sounding indicates a very steep 
slope in this position, equal to 1 in 1-9, and off the western shore further 
north a similar steep gradient is indicated by a sounding of 36 feet 
taken about 100 feet from the shore, equal to 1 in 2-8. The soundings 
reveal, further, an ill-defined shallow ridge, running in a north and 
south direction across the wide portion of the loch, covered by less than 
30 feet of water, with deeper water on both sides. The area of the lake- 
floor covered by less than 25 feet of water is about 23 acres, or 64 per 
cent, of the entire area of the loch. Loch nan Eun was surveyed on 
July 2, 1903 ; its elevation above the sea could not be determined from 
bench-mark, but, estimated from spot-levels, its elevation must be about 
2575 feet. There is evidently very little variation in the level of the 
surface of the water, since no drift-mark indicating a higher level could 
be seen, and a fall of a few inches would cease to feed the outflowing 
burn, which forms a waterfall a few yards from the loch, the top of the 
fall being at nearly the same level as the loch. 

Temperature Observations. The temperature of the surface water on 
commencing the survey at 10.30 a.m. was 50 0< 0, and a series of tem- 
peratures taken at noon in the deepest part of the loch gave the 
following results : 

Surface 50'8 Fahr. 

25 feet 50'5 ,, 

45 49'8 

Lochs Craiglush, Lowes, Butterstone, Clunie, Drumellie, Rae, 
Fingask, White, Black, and the Stormont lochs form a connected series 
of lochs all draining into the Lunan burn, which flows into the river 
Isla shortly before its junction with the river Tay; they all contain 
pike and perch, and trout also are taken in Lochs Craiglush, Lowes, and 
Drumellie. The group nearest the source of the Lunan burn consists 
of Lochs Craiglush, Lowes, and Butterstone. 

Loch of Craiglush (see Plate XXIX.). The Loch of Craiglush is 
situated in Drumbuie wood near Dunkeld, and is almost surrounded by 
trees. Its shores are weedy, and where the Lunan burn enters there is 
a large grassy flat formed of material brought down by the stream. It 
trends in a north-east and south-west direction, and is over half a mile 
in length, with a maximum breadth of over a quarter of a mile, the 
mean breadth being nearly one-fifth of a mile, or 32 per cent, of the 
length. Its waters cover an area of about 70 acres, or over one-tenth 
of a square mile, and it drains an area of about 5| square miles an 
area 52 times greater than the area of the loch. Over 50 soundings were 
taken, the maximum depth observed being 44 feet. The volume of 
water contained in the loch is estimated at 49,079,000 cubic feet, and 
the mean depth at 16 feet, or 37 per cent, of the maximum depth. The 



THE FRESH- WATER LOCHS OF SCOTLAND. 101 

length of the loch is 70 times the maximum depth, and 190 times the 
mean depth. The Loch of Craiglush forms a simple basin, the bottom 
sloping gradually down on all sides towards the deepest part without 
any pronounced irregularities. The maximum depth of 44 feet was 
observed in two places opposite the entrance of the Lunan burn, 
approximately in the centre of the loch, but nearer the western shore 
and the southern end. The area of the lake-floor covered by less than 
20 feet of water is about 51 acres, or 73 per cent, of the total area of the 
loch ; that covered by water between 20 and 40 feet in depth is nearly 
15 acres, or 21 per cent. ; and that covered by more than 40 feet of water 
is over 4 acres, or 6 per cent, of the entire area of the loch. Loch 
Craiglush was surveyed on June 2, 1903, and the height of the surface 
of the water above sea-level was determined by levelling from bench- 
mark as being 327*6 feet, the same as Loch of Lowes, into which it 
flows. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch at 7.45 a.m. gave the following results: 

Surface 61'2Fahr. 

5 feet 61'3 

8 61'2 

9 , 57-4 

10 54-5 

20 52-0 

30 , 50-0 

42 ., 49-0 

This series shows a rapid fall in the temperature between 8 and 10 
feet, amounting to 6-7 (a fall of 3-8 between 8 and 9 feet, and of 2-9 
between 9 and 10 feet), the extreme range of temperature from surface 
to bottom amounting to 12 0> 2. 

Loch of Lowes (see Plate XXIX.). The Loch of Lowes, like the Loch 
of Craiglush, is surrounded by trees ; its shores are mostly composed of 
stony debris, and weeds are abundant off the south-western shore where 
the artificial channel from the Loch of Craiglush enters. It trends in a 
north-east and south-west direction, and is 1^ miles in length, with a 
maximum breadth of over half a mile, the mean breadth being more 
than a quarter of a mile, or 24 per cent, of the length. Its waters cover 
an area of about 218 acres, or over one-third of a square mile, and it 
drains directly an area of nearly 2 square miles, but since it receives 
the outflow from the Loch of Craiglush its total drainage area is about 
7 square miles, an area nearly 23 times greater than the area of the 
loch. Over 60 soundings were taken, the maximum depth observed 
being 53 feet. The volume of water contained in the loch is estimated 
at 193,973,000 cubic feet, and the mean depth at nearly 20| feet, or 
39 per cent, of the maximum depth. The length of the loch is 138 times 



102 BATHYMETR1CAL SURVEY OF 

the maximum depth, and 360 times the mean depth. The Loch of 
Lowes forms on the whole a simple basin, but with here and there 
minor undulations of the bottom. The maximum depth of 53 feet was 
observed approximately in the centre of the loch, but a short distance 
to the north of it a sounding of 42 feet was taken apparently surrounded 
on all sides by shallower water, and to the west a depth of 7 feet was 
observed with deeper water all round. Generally speaking, the slope 
of the bottom is gentle, there being no evidence of any steep gradients. 
The area of the lake-floor covered by less than 20 feet of water is about 
120 acres, or 55 per cent, of the total area of the loch ; that covered by 
water between ^0 and 40 feet in depth is about 79 acres, or 26 per cent. ; 
and that covered by more than 40 feet of water is about 19 acres, or 
9 per cent, of the entire area of the loch. The Loch of Lowes was 
surveyed on June 2, 1903, the same day as the Loch of Craiglush, and 
the elevation of the two lochs above the sea was found by levelling to be 
identical, viz., 327 - 6 feet. When levelled by the Ordnance Survey 
officers on July 13, 1899, the elevation was found to be 327-9 feet above 
the sea. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch at 1.15 p.m. gave the following results : 

Surface 60'OFahr. 

10 feet 59-5 ,, 

13 57'0 

15 52-2 

20 51-0 

30 50-2 ,, 

40 50-0 

50 ,, 50'0 ,, 

This series shows a range of 10 in the temperature throughout the 
50 feet of water, the greatest fall being one of 4 0> 8 between 13 and 15 
feet. Compared with the temperatures taken in the Loch of Craiglush 
earlier in the day, this series shows a smaller range (the temperature at 
the surface being lower and at the bottom higher, notwithstanding the 
greater depth), and the position of the greatest fall in the temperature 
was observed at a greater depth, viz., between 10 and 15 feet, as 
compared with between 8 and 10 feet in the Loch of Craiglush. 

Loch of Butter stone (see Plate XXIX.). The Loch of Butterstone 
(or Butterston) is, like the two neighbouring lochs, to a large extent 
surrounded by trees; its shores are sandy or weedy, and many coots 
nest among the weeds. It is almost circular in outline, the greatest 
diameter (or length) from north-east to south-west being about three- 
fifths of a mile, while the maximum breadth from north-west to south- 
east is about half a mile, the mean breadth being over a quarter of a mile, 
or 50 per cent, of the length. Its waters cover an area of about 108 acres, 



THE FRESH- WATER LOCHS OF SCOTLAND. 103 

or one-sixth of a square mile, and it drains directly an area of over two- 
thirds of a square mile, but since it receives the outflow from Lochs 
Craiglush and Lowes, its total drainage area is about 8J square miles 
an area 49 times greater than the area of the loch. Over 50 soundings 
were taken, the maximum depth observed being 25 feet. The volume 
of water contained in the loch is estimated at 53,238,000 cubic feet, 
and the mean depth at 11| feet, or 45 per cent, of the maximum depth. 
The length of the loch is 122 times the maximum depth and 271 times 
the mean depth. The Loch of Butterstone forms a simple basin, the 
maximum depth of 25 feet being observed approximately in the centre 
of the loch, but nearer the western and southern shores. The deeper 
water approaches much closer to the western than to the eastern shore, 
off which the shallow water extends some distance into the loch, 
especially opposite the point at the outflow, where the 10-feet contour- 
line makes a great bend inward; this bend affects also the 20 -feet 
contour-line, so that the 20-feet basin becomes somewhat crescent- 
shaped. The area of the lake-floor covered by less than 10 feet of water 
is about 52 J acres, or 48J per cent, of the entire area of the loch ; that 
covered by water between 10 and 20 feet in depth is about 39J acres, or 
36 \ per cent. ; and that covered by more than 20 feet of water is about 
16 acres, or 15 per cent, of the total area of the loch. The Loch of 
Butterstone was surveyed on June 1, 1903, and the surface of the water 
was found by levelling from bench-mark to be 314'4 feet above sea-level. 
The Ordnance Survey officers determined the level on July 31, 1899, as 
being 314*8 feet above the sea. 

Temperature Observations. Temperature observations were taken 
in the deepest part of the loch in the afternoon of June 1, 1903, with 
the following results : 

Surface 63-0 Fahr. 

5 feet ... 62-8 

8 , 62-5 

10 , 57'0 

25 53 

This series shows a range from surface to bottom of 10, the greatest 
fall being one of 5-5 between 8 and 10 feet. The water was warmer at 
all depths than in Lochs Craiglush and Lowes at corresponding depths ; 
the greatest decrease of temperature was observed at the same depth as 
in Loch Craiglush ; the range of temperature was the same as that in 
Loch Lowes, although there is only half the depth of water. 

Loch of Clunie (see Plate XXX.). The Loch of Cluuie lies in a well- 
wooded valley, and is surrounded by cultivated ground, except at 
Forneth woods. The castle on the island in the loch, which seems to be 
artificial, is said to have been the birthplace of the Admirable Crichton. 
On this island a pair of herons built their nest in 1903, but nest and 



104 BATHYMETRICAL SURVEY OF 

young were destroyed by excursionists. Near the middle of the north 
side of the loch, and about 100 yards from the shore, is a mound of 
stones (two of which were above the water on the date of the survey), 
said to have been put down to indicate a sandbank. The Lunan burn 
at the exit of the loch is a long weedy stretch with no perceptible 
current, the fall to the Loch of Drumellie being only 10 feet in a mile. 
The Loch of Clunie is triangular in outline, with the apex pointing 
south. The diameter from east to west and from north to south is 
nearly equal, the length from east to west being rather less than two- 
thirds of a mile, while the maximum breadth is slightly less, the mean 
breadth being one-third of a mile, or 55 per cent, of the length. Its 
waters cover an area of 134 acres, or over one-fifth of a square mile, 
and it drains directly an area of nearly 8 square miles, but since 
it receives the outflow from the Lochs of Butterstone, Lowes, and 
Craiglush, its total drainage area is over 16^ square miles an area 
nearly 78 times greater than the area of the loch. Over 80 soundings 
were taken, the maximum depth observed being 69 feet. The volume 
of water contained in the loch is estimated at 170,265,000 cubic feet, 
and the mean depth at 29 feet, or 42 per cent, of the maximum depth. 
The length of the loch is 47 times the maximum depth, and 112 times 
the mean depth. The Loch of Clunie forms, generally speaking, a 
simple basin, but with a few minor undulations of the bottom. The 
25-feet basin corresponds approximately with the outline of the loch, 
but the 50-feet basin is somewhat irregular in outline, owing to two 
elevations of the lake-floor : (1) Near the north-east angle of the loch, 
where a sounding of 24 feet was taken, with depths of 33 and 35 feet 
on one side and depths of 52 and 69 feet on the other ; and (2) a short 
distance to the west, where a depth of 45 feet was observed, with 52 
feet on one side and 60 feet on the other. These two elevations give 
rise to a peculiar constriction in the outline of the 50-feet basin, 
and the shallower elevation is the more striking because of its close 
proximity to the deepest part of the loch, the maximum depth of 69 
feet having been found comparatively close to the eastern shore. A 
moderately steep slope was observed off the northern shore, opposite 
the east lodge of Forneth House, where a depth of 14 feet was found 
about 60 feet from the shore, equal to a gradient of 1 in 4'3. The area 
of the lake-floor covered by less than 25 feet of water is about 68 acres, 
or 51 per cent, of the total area of the loch; that covered by water 
between 25 and 50 feet in depth is about 39 acres, or 29 per cent. ; and 
that covered by more than 50 feet of water is about 27 acres, or 20 per 
cent, of the entire area of the loch. The Loch of Clunie was surveyed 
on June 4, 1903, and the elevation of the lake-surface above the sea 
was determined, by levelling from bench-mark, as being 156*55 feet; 
when levelled by the Ordnance Survey officers on September 12, 1899, 
the elevation was found to be 156-3 feet. 



THE FRESH- WATER LOCHS OF SCOTLAND. 105 

Temperature Observations. Temperature observations taken at 
6.30 p.m. in the deepest part of the loch gave the following results : 



Surface ... 


62, 3 Fa 


IT. 


5 feet 
K) 


62-0 , 
54 -2 , 


Ifl 


52-4 , 


25 


49-0 , 


50 . 


47 -4 , 


65 . 


47 '2 



This series shows a range of temperature from surface to bottom 
amounting to 15'l, the greatest fall being one of 7 0- 8 between 5 and 10 
feet, there being a further fall of 3-4 between 15 and 25 feet. 

Loch of Drumellie (see Plate XXX.). The Loch of Drumellie (or 
Marlee Loch) lies about a mile to the east of the Loch of Clunie, and is 
surrounded by cultivated ground, the fields sloping gently up on all 
sides. Its shores are stony or weedy, and the narrow portion leading 
to the outflow is quite choked up with weeds, except for an artificial 
channel about 4 feet deep leading to the landing-stage, where the burn 
flows out over a weir. Large yellow masses of decaying vegetable matter 
were floating everywhere. The loch is about seven-eighths of a mile in 
length, with a maximum breadth of nearly half a mile, the mean breadth 
being nearly one-third of a mile, or 37 per cent, of the length. Its waters 
cover an area of about 175 acres, or over a quarter of a square mile, and 
it drains directly an area of over 6^ square miles, but since it receives 
the outflow from the Loch of Clunie and from Rae Loch, its total 
drainage area is about 23 J square miles an area 86 times greater than 
the area of the loch. Over 70 soundings were taken, the maximum depth 
observed being 58 feet. The volume of water contained in the loch is 
estimated at 221,902,000 cubic feet, and the mean depth at 29 feet, or 
50 per cent, of the maximum depth. The length of the loch is 78 times 
the maximum depth and 156 times the mean depth. The Loch of 
Drumellie forms a flat-bottomed basin, the bottom sinking in two 
places below the 50-feet line, with shallower water between. The 
south-eastern 50-feet basin is based upon two soundings of 51 feet, 
while in the north-western one the maximum depth of 58 feet was 
observed, situated less than a quarter of a mile from the west end 
of the loch. The average slope of the bottom is gentle, the steepest 
slope observed being about midway along the southern shore, where 
a sounding of 20 feet was taken about 100 feet from the shore, giving 
a slope of 1 in 5. The area of the lake-floor covered by less than 
25 feet of water is about 72 acres, or 41 per cent, of the total area of 
the loch; that covered by water between 25 and 50 feet in depth is 
about 83 acres, or 47 per cent. ; and that covered by more than 50 feet 
of water is about 20 acres, or 12 per cent, of the entire area of the loch. 



106 BATHYMETRICAL SURVEY OF 

The fact that the area between the 25- and 50-feet contour-lines is 
greater than the area between the shore and the 25 -feet line proves the 
flat-bottomed nature of the basin, as well as the fact that the mean 
depth is fully half the maximum depth. The Loch of Drumellie was 
surveyed on the same day as the Loch of Clunie, June 4, 1903 ; the 
elevation above the sea was determined by levelling from bench-mark as 
being 146*7 feet. The Ordnance Survey officers found the level of the 
lake-surface to be 147 feet above the sea on September 19, 1899. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch at 11.30 a.m. gave the following results: 

Surface 0'2 Fahr. 

10 feet 59 

15 53-7 

20 50-7 

30 49 5 

40 49-2 

58 ,, 487 ,, 

This series shows a range of temperature from surface to bottom of 
11'5, the greatest fall being one of 5 0< 3 between 10 and 15 feet, with 
a further fall of 3 between 15 and 20 feet. Compared with the 
temperatures taken in the Loch of Clunie in the evening of the same 
day, this series shows a much smaller range of temperature, the surface 
temperature being 2 lower and the bottom temperature 1 0< 5 higher, 
although the difference in depth is only 7 feet ; the position of greatest 
fall in the temperature is nearer the surface in the Loch of Clunie, 
and the amount of fall is greater. 

Rae Loch (see Plate XXX.). Rae Loch (or Ardblair Loch) lies a 
quarter of a mile to the east of the Loch of Drumellie, into which it 
flows, and about a mile to the west of Blairgowrie. It is surrounded 
by low fields and wooded country, and its shores are all weedy, while the 
western portion of the loch is quite filled with weeds. The water 
formerly stood at a higher level, and frequently flooded the road on the 
north side ; it was consequently lowered about 10 feet by a cutting, 
which has since, however, become choked up. It is under half a mile 
in length, less than one-fifth of a mile in maximum breadth, the mean 
breadth being about one-ninth of a mile, or 25 per cent, of the length. 
Its waters cover an area of about 30 acres, and it drains an area seven 
times greater an area of over one-third of a square mile. Over 30 
soundings were taken, the maximum depth observed being 16 feet. 
The volume of water is estimated at 8,727,000 cubic feet, and the mean 
depth at 6J feet, or 31 per cent, of the maximum depth. The deeper 
water occurs near the eastern end, off which the slope is steep ; at one 
point a sounding of 10 feet was taken only 20 feet from the shore, giving 
a gradient of 1 in 2. The area of the lake-floor covered by less than 



THE FRESH-WATER LOCHS OF SCOTLAND. 107 

10 feet of water is about 24 acres, or 80 per cent, of the total area of the 
loch. Rae Loch was surveyed on June 23, 1903, and the level of the 
lake-surface above the sea was determined, by levelling from bench- 
mark, as 195'2 feet. 

Temperature Observations. Temperatures taken in the deepest part 
gave the following results : 

Surface 60'8 Fahr. 

5 feet 60'5 

10 57'9 

15 57'l 

The range of temperature throughout the 15 feet of water was 3'7, 
there being a fall of 2'6 between 5 and 10 feet. 

Fingask Loch (see Plate XXX.). Fingask Loch lies about three- 
quarters of a mile to the south-east of Rae Loch, and 1J miles to the 
south-west of Blairgowrie. It is surrounded by low cultivated ground, 
and weeds occur in the north-western angle of the loch and near the 
shore in other places, but not in any great abundance. It receives the 
outflow from White Loch by a mill lade, and it flows into the Lunan 
burn by a short sluggish stream. It is over one-third of a mile in 
length from north-west to south-east, with a maximum breadth of a 
quarter of a mile, the mean breadth being about one-seventh of a mile, 
or 41 per cent, of the length. Its waters cover an area of over 32 acres, 
and it drains directly an area of about one-sixth of a square mile, but, 
since it receives the outflow from the White Loch, its total drainage area 
is over a quarter of a square mile an area 4J times greater than the 
area of the loch. Nearly 40 soundings were taken, the maximum depth 
observed being 48 feet. The volume of water is estimated at 32,182,000 
cubic feet, and the mean depth at nearly 23 feet, or 48 per cent, of the 
maximum depth. Fingask Loch forms a simple basin, the bottom 
sloping down gradually on all sides to the deepest part, which is, 
approximately, centrally placed. The north-western angle is shallow 
and obstructed by weeds, but the remainder of the loch is comparatively 
deep, and forms a sub-circular basin. The slope of the bottom is in 
places moderately steep, as, for instance, off the northern shore, where 
a sounding of 20 feet was taken about 80 feet from the shore, giving a 
gradient of 1 in 4. The area of the lake-floor covered by less than 
10 feet of water is about 9 acres, or 27 \ per cent, of the total area of the 
loch ; that covered by water between 10 and 25 feet in depth is about 
8J acres, or 26 J per cent. ; that covered by more than 25 feet of water is 
about 15 acres, or 46 per cent, of the entire area of the loch. This last 
percentage indicates the flat-bottomed character of the basin. Fingask 
Loch was surveyed on June 19, 1903, and its elevation above the sea 
was determined by levelling from the White Loch (which was surveyed 
on the same day) as being 140*6 feet. 



108 BATHYMETRICAL SURVEY OF 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch in the afternoon of June 19, 1903, gave the 
following results : 

Surface 58'8 Fahr. 

10 feet 57'6 

20 55-3 

30 49-4 

45 48-7 

This series shows a range of temperature from surface to bottom of 
about 10, there being a fall of about 6 between 20 and 30 feet. 

White Loch (see Plate XXX.). The White Loch lies immediately 
to the east of Fingask Loch, into which it flows by an artificial mill-lade, 
and the water has apparently been raised several feet by damming, in 
order to supply the mill. At the east end of the loch, in the direction of 
the Black Loch, a copious burn flows out of the bank into the White 
Loch, but there is no evidence that it comes from the Black Loch, and 
the local people think the burn has its source in a spring. The eastern 
portion of the loch, called the Eie Loch, is separated from the larger 
and deeper portion by a narrow constriction ; it is shallow, and almost 
filled with weeds, with a central depression 15 feet in depth. Tradition 
says this was once a separate loch, and that the connection was cut, the 
depth in the constriction being 2 feet. The loch is surrounded by 
gently sloping fields and wooded ground. It is about one-third of a 
mile in length, with a maximum breadth of one-seventh of a mile, the 
mean breadth being one-fourteenth of a mile, or 20 per cent, of the 
length, and its waters cover an area of about 15 acres. Over 40 
soundings were taken, the maximum depth observed being 32 feet. 
The volume of water is estimated at 8,425,000 cubic feet, and the mean 
depth at 13 feet, or 41 per cent, of the maximum depth. The length of 
the loch is 56 times the maximum depth and 138 times the mean depth. 
The western portion of the White Loch forms a simple basin, the 
bottom sloping gently down on all sides to the deepest part, which is 
approximately centrally placed. There is no evidence of any pronounced 
irregularity of the lake-floor, nor of any steep slope. The area of the 
lake-floor covered by less than 10 feet of water is about 8 acres, or 52 
per cent, of the total area of the loch ; that covered by water between 
10 and 25 feet in depth is over 4 acres, or 29 per cent. ; and that 
covered by more than 25 feet of water is about 3 acres, or 19 per cent. 
White Loch was surveyed on the same day as Fingask Loch (June 19, 
1903), and its elevation above the sea was determined, by levelling from 
bench-mark, as being 153 '7 feet. 

Temperature Observations. Temperatures taken in the deepest part 
of the loch gave the following results : 



THE FRESH- WATER LOCHS OF SCOTLAND. 109 

Surface 59OFahr. 

10 feet 58-0 

2<) ,, 52-5 

30 50-2 

This series shows a range of 8'8 in the temperature of the water from 
surface to bottom, there being a fall of 5*5 between 10 and 20 feet. 
Compared with the temperatures taken in Fingask Loch on the same 
day, this series indicates that the temperature of the upper layers of 
water was comparable in both lochs, but at 20 feet the temperature was 
nearly 3 lower than at that depth in the larger loch, the position of 
the great fall in the temperature being nearer the surface in the smaller 
loch. 

Black Loch (see Plate XXX.). The Black Loch lies immediately 
to the east of the White Loch, the main road from Perth to Blairgowrie 
passing between them. Neither inflow nor outflow was observed, but 
if the water were to rise 6 or 8 feet it might overflow by the channel 
under the road into the White Loch. It is almost surrounded by woods, 
and the shores are weedy. It is over a quarter of a mile in length, 
nearly one-tenth of a mile in maximum breadth, and its waters cover 
an area of about 8 acres. Nearly 30 soundings were taken, and the 
maximum depth observed was 7 feet. The voluma of water is estimated 
at 1,611,000 cubic feet, and the mean depth at 4| feet, or 68 per cent, 
of the maximum depth. The loch is almost of uniform depth, only 
three of the soundings being under 5 feet, and these were near the east 
end, so that the great body of water is from 5 to 6 feet in depth, the 
area of the lake-floor covered by more than 5 feet of water being about 
5 acres, or 64 per cent, of the total area of the loch. It was surveyed 
on June 23, 1903, by means of a portable boat lent by Mr. Anderson, 
carried over from Druidsmere, and the elevation above the sea was 
determined, by levelling from bench-mark, as being 162-8 feet. 

Temperature Observations. The temperature of the surface water 
in the main body of the loch was 60'l, while in the eastern portion it 
was 59'0. The water in the eastern basin was clearer as well as colder, 
as though there might be a spring there. Temperatures taken in the 
deepest part of the loch gave the following results : 

Surface 60'l Fahr. 

3 feet ... 60-0 ,, 

4 59-8 

5 , 58'5 

6 57 c 'l 

showing a range of 3*0 throughout the 6 feet of water. 

To the south-west of the Black Loch lies Hare Myre, which was 
visited on June 22, 1903, but could not be sounded because no boat was 
available. The keeper said it was all shallow, and that the oars when 



110 BATHYMETRICAL SURVFA 7 OF 

rowing stirred up the mud everywhere, the depth probably not exceeding 
2 feet. More than two-thirds of the superficial area is overgrown with 
weeds, there being a very little open water of a black colour. Neither 
inflow nor outflow was seen, but a drain was cut at some remote time to 
conduct the water to the south-west, where it joined the burn flowing 
from Stormont Loch to the Lunan burn. The loch does not now rise to 
overflow, and the water is stagnant, but looks clearer than that in the 
Stormont Loch. 

The term Stormont Lochs is ^sometimes applied to the group of small 
lochs in this neighbourhood, including Loch Bog (or Stormont Loch), 
Monk Myre, Hare Myre, Black, White, Fingask, and Rae. Myriads 
of water-fowl breed on these lochs, and ducks of several species were 
nesting on the artificial island in Stormont Loch at the time of the 
survey. 

Stormont Loch (see Plate XXX.). Stormont Loch (or Loch Bog) lies 
immediately to the east of Hare Myre. It is a stagnant bog in a flat 
country, surrounded by woods and fields, and it receives no water 
except rains. It rarely rises high enough to overflow, but in February, 
1903, it did so, the outflow being artificial and leading to the Lunan 
burn. The water is turbid, light brown in colour, and dense with 
animals so much so that the tow-nets could only be used for a very 
short time. About half the area of the loch is unapproachable on 
account of weeds, and the other half is very uniform in depth (2 to 3 
feet), and free from weeds. The keepers say that the mud on the bottom 
is of great depth, 18-feet poles having been sunk in it, and that it has 
accumulated greatly of late years. It is said that within the memory 
of old men now living there was a depth of 17 feet near where the boat- 
house was built (of which the remains are still visible). Stormont Loch 
is about two-thirds of a mile in length, and one-third of a mile in 
maximum breadth, the mean breadth being over one-sixth of a mile, 
or 27 per cent, of the length. Its waters cover an area of about 74 J 
acres, and the maximum depth of 3 feet was observed in several places 
near the eastern shore. The volume of water is estimated at 4,867,000 
cubic feet. It was surveyed on June 22, 1903, and its elevation above 
the sea was determined by levelling from bench-mark as 168-1 feet, 
which is identical with the level when visited by the Ordnance Survey 
officers on June 26, 1900. The temperature of the surface water at 
1 p.m. on June 22, 1903, was 64-0. 

Monk Myre (see Plate XXX.). Monk Myre lies about half a mile 
to the east of the Stormont Loch, but it flows in the opposite direction 
by the Monkmyre burn into the river Ericht; there are no inflowing 
burns. It is surrounded by flat grassy country, and is divided into two 
portions by a narrow constriction, through which it is now impossible to 



THE FRESH- WATER LOCHS OF SCOTLAND. Ill 

take a boat. The smaller western portion is mostly overgrown by weeds, 
with a very little open water, and never entirely freezes over, owing 
probably to the existence of numerous springs. Monk My re is over 
half a mile in length, with a maximum breadth of over one-seventh of a 
mile, the mean breadth being about one-thirteenth of a mile, or 14 per 
cent, of the length, and its waters cover an area of about 25 acres. Over 
30 soundings were taken, and the maximum depth observed was 12 feet. 
The volume of water is estimated at 5,552,000 cubic feet, and the mean 
depth at 5 feet, or 42 per cent, of the maximum depth. The loch is 
a shallow basin with rather uneven floor ; the deepest part is towards 
the northern shore, where neighbouring soundings of 10 and 12 feet 
were taken, the remaining soundings being under 10 feet. The area 
of the lake-floor covered by less than 10 feet of water is equal to 98 \ 
per cent, of the total area. Monk Myre was surveyed on June 20, 1903, 
but its elevation above the sea could not be ascertained. Temperatures 
taken at 7 a.m. gave 55-8 at the surface and at a depth of 10 feet. 

Long Loch and Pitlyal Loch form the headwaters of the Dighty 
burn, which flows eastward and enters the estuary of the Tay at 
Monifieth; a burn flows from Long Loch to Pitlyal Loch. 

Long Loch (see Plate XXX.). The Long Loch is bordered on the 
west by steep, grassy hills, while the eastern shore is low and wooded. 
No burns of any size enter the loch, but there are many springs on 
the hillside to the west. It contains pike and perch. The outflow is 
artificial, by dam and sluice ; but at the time of the survey the water 
was very low, and very little water was flowing out at the sluice. The 
dotted line on the map shows approximately the shore-line on the date 
of the survey, and the water would have to rise 4J feet to reach the 
overflow. Long Loch trends in a north-east and south-west direction, 
and is very peculiar in outline, presenting a close resemblance to a dog's 
body and head without legs, the portion represented by the dog's nose 
being filled with weeds. It is nearly three-quarters of a mile in length, 
with a maximum breadth of over a quarter of a mile, the mean breadth 
being one-sixth of a mile, or 24 per cent, of the length. Its waters 
cover an area of about 74 acres. Over 50 soundings were taken, the 
maximum depth observed being 42 feet. The volume of water contained 
in the loch is estimated at 31,893,000 cubic feet, and the mean depth 
at 10 feet, or 24 per cent, of the maximum depth. The length of the 
loch is 88 times the maximum depth, and 373 times the mean depth. 
Generally speaking, the loch forms a simple basin, with a few minor 
undulations of the bottom, and the slope is steeper off the western 
than off the eastern shore. The maximum depth of 42 feet was observed 
near the centre of the loch, but considerably nearer the western than 
the eastern shore. In this locality the slope is moderately steep, a 
sounding of 12 feet being recorded about 50 feet from the shore, giving 



112 BATHYMETRICAL SURVEY OF 

a gradient of 1 in 4-2. The area of the lake-floor covered by less than 
10 feet of water is about 52 acres, or 70 per cent, of the total area of 
the loch; that covered by water between 10 and 25 feet in depth is 
about 18 acres, or 25 per cent. ; and that covered by more than 25 feet 
of water is about 4 acres, or 5 per cent, of the entire area of the 
loch. Loch Long was surveyed on June 24, l)03, and its elevation 
above the sea was determined, by levelling from bench-mark, as 724-0 
feet. 

Temperature Observations. Temperatures taken in the deepest part 
of the loch gave the following results : 

Surface 58'4Fahr. 

10 feet 57'0 

15 -.. ... 55-4 ,, 

20 54-0 ,, 

40 53-2 ,, 

This series shows a range of temperature throughout the 40 feet of 
water of 5-2, there being a fall of 3 between 10 and 20 feet. 

Pitlyal Loch (see Plate XXX.). Pitlyal Loch (or Round Loch, or 
Thriepley Loch) lies about a quarter of a mile to the south-east of Long 
Loch, and is surrounded by gently sloping cultivated fields. There is 
a fringe of weeds all round the shore. Grebe and coots were seen, and 
there were swans on the small islet with bushes about 100 feet north- 
west of the boathouse. The outflow to the Dighty burn is by artificial 
dam and sluice; the water may rise 2 to 3 feet above its level on the 
date of the survey. The loch is well described by its name " Round 
Loch," for it is subcircular in outline, though rather longer from north 
to south than from east to west. It is over one-fifth of a mile in length, 
with a maximum breadth of about one-seventh of a mile, the mean 
breadth being about one-ninth of a mile, or 52 per cent, of the length, 
and its waters cover an area of about 15 acres. Thirty soundings were 
taken, the maximum depth observed being 19 feet. The volume of 
water is estimated at 5,347,000 cubic feet, and the mean depth at 
8J feet, or 44 per cent, of the maximum depth. Pitlyal Loch forms a 
simple basin, but the deeper water is found towards the western shore, 
so that the slope of the bottom is steeper off that shore than off the 
eastern shore; a sounding of 11 feet was taken about 100 feet from the 
western shore, and the maximum depth of 19 feet was recorded about 
150 feet from that shore. The area of the lake-floor covered by less 
than 10 feet of water is nearly 10 acres, or 65 per cent, of the total 
area of the loch. Pitlyal Loch was surveyed on the same day as Long 
Loch (June 24, 1903), and its elevation above the sea was determined 
by levelling from bench-mark as being 606-5 feet. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



113 



Temperature Observations. ^Temperature observations gave the 
following results : 



Surface 

10 feet 

11 

12 

13 , 



59OFahr. 
59 O 
58 -8 
55 "8 
55-0 



This series shows that the upper 10 feet of water had a uniform 
temperature, but between 11 and 12 feet there was a fall of 3, the 
extreme range from surface to bottom being 4. 

Loch Freuchie (see Plate XXXI.). Loch Freuchie (or Fraochie), 
near Amulree, is a very pretty loch amid pastoral scenery, the grassy 





FIG. 25. LOCH FBEUCHIE, LOOKING S.E. FBOM BBIDGE OVER INLET. 

(Photograph by R. Dykes.) 



shores sloping gently up on both sides, with here and there patches of 
wood. It was formerly a good trout loch, but in recent years it has 
been overrun by pike ; steps have been taken, however, to keep down 
the pike, and the fishing is now improving. It flows by the river Bran 
into the river Tay at Dunkeld. Loch Freuchie trends in a north- 
west and south-east direction, widest in the north-western half and 
narrowing towards the south-east end. It is If miles in length, with a 
maximum breadth of nearly half a mile, the mean breadth being about 
one-third of a mile, or 18 per cent, of the length. Its waters cover an 
area of about 348 acres, or over half a square mile, and it drains an 
area 55 times greater an area of over 23 square miles. Nearly 90 
soundings were taken, the maximum depth observed being 62 feet. The 
volume of water contained in the loch is estimated at 346,564,000 cubic 
feet, and the mean depth at 23 feet, or 37 per cent, of the maximum 

i 



114 BATHYMETRICAL SURVEY OF 

depth. The length of the loch is 148 times the maximum depth and 402 
times the mean depth. Loch Freuchie forms on the whole a simple 
basin, but with a few minor undulations of the bottom. The 25-feet 
basin is sinuous in outline, especially towards the south-east end, and is 
over 1J miles in length, approaching close to the north-west end, but 
distant less than a quarter of a mile from the south-east end. The 
50-feet basin, half a mile in length, is contained in the northern half of 
the loch, and nearer the eastern than the western shore, the maximum 
depth of 62 feet having been observed in two places, with soundings of 
60 feet between them. Cones of alluvium have been formed at the 
mouths of the Turrerich burns at the northern angle of the loch, and at 
the entrance of the Allt a' Mhuilimi about midway along the western 
shore. The area of the lake-floor covered by less than 25 feet of water 
is about 225 acres, or 65 per cent, of the total area of the loch ; that 
covered by water between 25 and 50 feet in depth is about 95 acres, or 

27 per cent. ; and that covered by more than 50 feet of water is about 

28 acres, or 8 per cent, of the entire area of the loch. Loch Freuchie 
was surveyed on June 5, 1903, and the height of the surface of the 
water above the sea was determined, by levelling from bench-mark, as 
being 867-45 feet ; when levelled by the officers of the Ordnance Survey 
on August 17, 1899, the elevation was found to be 870-8 feet above 
sea-level. 

Temperature Observations, Temperature observations taken in the 
deepest part of the loch at 7 p.m. gave the following results : 

Surface 58'6 Fahr. 

10 feet 58-3 

15 57'6 ,, 

25 , 53'0 

40 50'0 ,, 

60 49-4 

This series shows a range of temperature from surface to bottom of 
9-2, there being a fall of 4-6 between 15 and 25 feet, and a further 
fall of 3-0 between 25 and 40 feet. 

Loch Hoil (see Plate XXXI.). Loch Hoil (or Oyl, or Thuill) lies to 
the south of Aberfeldy, and flows by the Cochill burn into the river 
Bran. It contains trout, perch, grayling, and gudgeon. It is sur- 
rounded by low, rounded, hummocky, heather-clad hills. Its shores are 
stony ; the bay leading to the outflow is very shallow and full of weeds. 
It is very irregular in outline, and over one-third of a mile in length 
from north-west to south-east, under one-third of a mile in maximum 
breadth from north-east to south-west, the mean breadth being one- 
seventh of a mile, or 43 per cent, of the length. Its waters cover an 
area of about 35 acres, and it drains an area six times greater an area 



THE FRESH- WATER LOCHS OF SCOTLAND. 115 

of over one-third of a square mile. Nearly 40 soundings were taken, 
the maximum depth observed being 46 feet. The volume of water is 
estimated at 29,271,000 cubic feet, and the mean depth at 19 feet, or 
42 per cent, of the maximum depth. The length of the loch is 40 times 
the maximum depth and 100 times the mean depth. Loch Hoil 
consists of a main body, which trends almost north and south, sending 
out an arm in an easterly direction leading to the outflow. This arm 
is shallow, while the body of the loch is comparatively deep; at the 
junction of the arm and body is a heap of stones about 200 feet from 
the eastern shore. The body of the loch forms a simple basin, the 
bottom sloping down on all sides towards the deepest part, which is 
approximately centrally placed, but rather nearer the northern than 
the southern end. The average slope of the bottom is gentle, the 
steepest gradient observed being one of 1 in 4-6 off the southern shore, 
where a sounding of 13 feet was taken 60 feet from the shore. The area 
of the lake-floor covered by less than 20 feet of water is about 24 acres, 
or 68 per cent, of the total area of the loch; that covered by water 
between 20 and 40 feet in depth is about 9 acres, or 26 per cent. ; and 
that covered by more than 40 feet of water is about 2 acres, or 6 per 
cent. The loch was surveyed on May 28, 1903, and, from spot-levels 
near the loch, it was calculated that the surface of the water was about 
1600 feet above the sea. 

Temperature Observations. Temperatures taken in the deepest part 
of the loch gave the following results : 

Surface 57'0 Fahr. 

10 feet ... 52-0 

20 48-0 

40 47'0 

This series shows a range of 10 from surface to bottom, there being 
a fall of 5 between the surface and 10 feet, and a further fall of 4 
between 10 and 20 feet. 

Loch Fender (see Plate XXXI.). Loch Fender lies to the north of 
Loch Freuchie, and flows by the Glenfender burn into the river Bran. 
It contains large trout, but the fishing, which is preserved, is uncertain, 
sometimes yielding splendid sport, at other times none at all. It was 
surveyed on the same day as Loch Freuchie by means of a boat kindly 
supplied by Mr. Bulloch of Kinloch. The Marquis of Breadalbane 
sounded Loch Fender about 40 years ago from a portable boat, and 
found a maximum depth of about 30 yards ( = 90 feet) ; the maximum 
depth recorded by the Lake Survey was 78 feet. Loch Fender is thus 
extremely interesting on account of its great depth, considering its 
small dimensions. The shores are rocky all round, and the southern 
shore is a steep slope of bare rock, rising gradually to Creag an Loch ; 



116 BATHYMETRICAL SURVEY OF 

at other places the shores are less steep, and surrounded by smooth, 
rounded, heather-covered hills. The water was very dark in colour, 
and, though there was apparently no great amount of inflow, there was 
a considerable outflow. Loch Fender is one-third of a mile in length 
from north-east to south-west, and one-fifth of a mile in maximum 
breadth, the mean breadth being over one-tenth of a mile, or 32 per 
cent, of the length. Its waters cover an area of over 22 acres, and it 
drains an area nine times greater an area of over one-third of a square 
mile. Nearly 60 soundings were taken, the maximum depth observed 
being 78 feet. The volume of water contained in the loch is estimated 
at 30,998,000 cubic feet, and the mean depth at 31| feet, or 41 per 
cent, of the maximum depth. The length of the loch is 22 times the 
maximum depth and 55 times the mean depth. Loch Fender forms a 
simple basin, the bottom sloping down on all sides to the deepest part, 
which is approximately centrally placed, but nearer the north-east than 
the south-west end, the maximum depth of 78 feet having been observed 
about 300 feet from the north-eastern shore. The average slope of the 
bottom is very steep, especially off the south-eastern shore, where were 
recorded soundings of 29 feet 20 feet from shore, 26 feet 30 feet from 
shore, and 17 feet 20 feet from shore, giving gradients of 1 in 0*7 and 
1 in 1-2. Off the north-western shore the gradient is gentler, and the 
north-west angle, where the burn flows into the loch, is comparatively 
shallow and obstructed by weeds. The area of the lake-floor covered 
by less than 25 feet of water is about 11 acres, or 51 per cent, of the 
total area of the loch ; that covered by water between 25 and 50 feet in 
depth is about 5 acres, or 21 per cent. ; and that covered by more than 
50 feet of water is about 6 acres, or 28 per cent, of the entire area of 
the loch. Loch Fender was surveyed on June 5, 1903, and, from spot- 
levels near the loch, it was estimated that the elevation of its surface 
was approximately 1888 feet above sea-level. 

Temperature Observations. Temperatures taken in the deepest part 
of the loch at 1 p.m. gave the following results: 

Surface 58-OFahr. 

5 feet 57-8 ,, 

10 52 -0 

15 ,, ... ... 4o-0 ,, 

25 ,, 44-0 f> 

50 43'0 

75 ... 42-4 

This series shows a range of temperature from surface to bottom 
amounting to 15-6, there being a fall of 12-8 between 5 and 15 feet 
(i.e. 5-8 between 5 and 10 feet, and 7-0 between 10 and 15 feet). The 
decrease of temperature in the layer of water between 10 and 15 feet is 
thus equal to l-4 per foot, whereas the fall is only 1 in the underlying 
layer between 15 and 25 feet. 



THE FRESH- WATER LOCHS OF SCOTLAND. 



117 



Loch Turret (see Plate XXXII.). Loch Turret, in Glen Turret, 
near Crieff, is used as the source of the water supply to the town of 
Crieff. It is a good trout loch, but strictly preserved, and is situated 
amid wild and beautiful scenery, the hills being steep and high on both 
sides, especially to the west, where crags border the loch. It flows by 
the Turret burn into the river Earn, and it receives the waters from 
the little Lochan Uaine, lying at the head of the glen, which was 
surveyed on the same day by request of the proprietor. Loch Turret 
trends in a north-west and south-east direction, and is widest towards 
the southern end, narrowing somewhat towards the northern end. It 
is over a mile in length, and over one-third of a mile in maximum 
breadth, the mean breadth being a quarter of a mile, or 24 per cent, of 







FIG. 26. LOCH TURRET., LOOKING N.W. 
(Photograph by R. Dykes.) 



the length. Its waters cover an area of about 164 acres, or a quarter 
of a square mile, and it drains an area 23 times greater an area of 
nearly 6 square miles. Seventy soundings were taken, the maximum 
depth observed being 79 feet. The volume of water contained in the 
loch is estimated at 227,718,000 cubic feet, and the mean depth at 
32 feet, or 40 per cent, of the maximum depth. The length of the 
loch is 70 times the maximum depth and 173 times the mean depth. 
Loch Turret forms on the whole a simple basin, the deeper water 
approaching nearer to the northern end and the western shore. The 
wide southern portion is comparatively shallow (under 20 feet), with 
one or two slight irregularities of the bottom, as, for instance, near the 
south-western angle of the loch, where soundings of 8 feet and 9 feet 



118 BATHYMETRICAL SURVEY OF 

were recorded, surrounded in each case by deeper water. These shallow 
soundings mark the position of a rocky ridge, said to cross the loch, and 
to be a continuation of the rocky ridge on the east shore, now used as a 
quarry. About midway along the eastern shore there is a slight con- 
striction in the outline of the loch at the entrance of the Allt Bhaltair, 
apparently due to the material brought down by that stream, and in 
this position a slight shoaling of the bottom in the centre of the loch is 
observable, the depth being 73 feet, with two soundings of 77 feet to the 
north, and soundings of 77 and 79 feet to the south. The 2 5 -feet basin 
is about three-quarters of a mile in length, approaching to within 100 
feet from the northern end, and a quarter of a mile from the southern 
end. The slope of the bottom is steeper off the western than off the 
eastern shore; near the middle of the western shore a sounding of 40 
feet was taken about 50 feet offshore, giving a gradient of 1 in 1-25. 
The area of the lake-floor covered by less than 25 feet of water is about 
85 acres, or 52 per cent, of the total area of the loch ; that covered by 
water between 25 and 50 feet in depth is about 36 acres, or 22 per 
cent. ; that covered by water between 50 and 75 feet in depth is about 
36 acres, or 22 per cent. ; and that covered by more than 75 feet of 
water is about 7 acres, or 4 per cent, of the entire area of the loch. 
The flat-bottomed character of the deep basin is well brought out by the 
fact that the area between the 25- and 50-feet contour-lines is almost 
identical with the area between the 50- and 75 -feet contours. Loch 
Turret was surveyed on June 9, 1903, and the elevation of the lake 
surface above the sea, measured from the spot-level 1145 on the east 
shore, was determined as being 1132 feet. The water in the loch was 
high on the date of the survey. 

Temperature Observations. The temperature of the surface water 
on commencing the survey at 9 a.m. was 60'0, and a series of tem- 
peratures taken later in the deepest part of the loch gave the following 
results : 

Surface ... 60 8 Fahr. 

10 feet ... 59-o ,, 

15 54-0 

25 477 

~>0 44-8 ,, 

75 44 -4 ,, 

This series shows a range of temperature from surface to bottom 
amounting to 16-4, there being a fall of 5-0 between 10 and 15 feet, 
one of 6-3 between 15 and 25 feet, and one of 3 between 25 and 50 
feet; the decrease of temperature between 10 and 15 feet was thus 
equal to 1 per foot of depth. 

Lochan Uaint (see Plate XXXII.). Lochan Uaine, at the head of 
Glen Turret, lies in a corrie; its shores are peat, and the bottom weedy. 






THE FRESH-WATER LOCHS OF SCOTLAND. 119 

In the middle of the loch towards the north end is a mud islet 2 or 3 
feet in length and a few inches above the water. Sir Patrick Keith 
Murray tried to drain the loch, but failed, and subsequently a rough 
dam was built at the outflow. The burn flowing from Lochan Uaine to 
Loch Turret passes among a series of very perfect moraine mounds. 
Lochan Uaine is a small shallow loch, about one-seventh of a mile in 
length, and covering an area of about 4J acres, with a maximum depth 
of 10 feet. The volume of water is estimated at 678,000 cubic feet, 
and the mean depth at 3J feet. Nearly 40 soundings were taken, but 
some of them have been omitted on the chart for lack of space. The 
deeper water occurs near the northern end, to the north-west of the 
mud islet; to the south-east of the islet the depth is under 5 feet. 
About 80 per cent, of the lake-floor is covered by less than 5 feet of 
water. Lochan Uaine was surveyed by request on the same day as 
Loch Turret, June 9, 1903; from spot-level, its elevation above the 
sea is about 1520 feet. The surface temperature at 2 p.m. was 67'0. 

PondofDrummond (see Plate XXXII.). The Pond of Drummond, 
within the policies of Drummond Castle, near Crieff, is a pretty 
artificial loch, well stocked with trout, but strictly preserved; it flows 
into the river Earn. It trends east and west, and is two-thirds of a 
mile in length, nearly one-third of a mile in maximum breadth, the 
mean breadth being one-fifth of a mile, or 31 per cent, of the length. 
Its waters cover an area of about 91 acres, and it drains an area four 
times greater, or over half a square mile. Sixty soundings were taken, 
the maximum depth observed being 12 feet. The volume of water is 
estimated at 20,157,000 cubic feet, and the mean depth at 5 feet, or 
43 per cent, of the maximum depth. The length of the loch is about 
300 times the maximum depth, and 700 times the mean depth. The 
Pond of Drummond is, on the whole, very shallow; it is only in the 
small narrow portion at the east end that the depth exceeds 8 feet, the 
maximum depth of 12 feet having been found in the extreme north- 
eastern angle of the loch near the outflow. Nearly 99 per cent, of the 
lake-floor is covered by less than 10 feet of water. It was surveyed on 
June 18, 1903, but its elevation above the sea could not be determined, 
because of inability to find bench-mark. The water in the loch was 
very low, the wooden jetty at the boathouse being 2 feet above water. 
The temperature of the surface water was 60-0. 

Loch Monzievaird (see Plate XXXII.). Loch Monzievaird (or 
Ochtertyre), within the grounds of Ochtertyre, near Crieff, flows into 
the river Earn; it contains pike, carp, and perch, but few, if any, 
trout. Its shores are said to be all reclaimed moorland, wooded and 
high on the north side, grassy slopes with scattered trees on the south 
side. The large island near the north-eastern end of the loch is covered 



120 BATHYMETRICAL SURVEY OF 

with trees and grass, and is said by Mr. Patrick Murray to be natural ; 
the small island to the south is artificial, composed of stones, with a 
submerged causeway running eastward to the shore; the island in the 
south-western portion of the loch is also artificial, built on piles, and 
is said to have been used as a prison. Loch Monzievaird trends in a 
north-east and south-west direction, being widest and deepest towards 
the south-western end ; there is a central constriction which divides the 
loch into two basins. It is over half a mile in length, with a maximum 
breadth of one-fifth of a mile, the mean breadth being over one-tenth 
of a mile, or 19 per cent, of the length. Its waters cover an area of 
about 37 acres, and it drains an area of 1J square miles an area 27 
times greater than the area of the loch. Over 60 soundings were taken, 
the maximum depth observed being 39 feet. The volume of water con- 
tained in the loch is estimated at 23,905,000 cubic feet, and the mean 
depth at nearly 15 feet, or 38 per cent, of the maximum depth. The 
length of the loch is 74 times the maximum depth, and 198 times the 
mean depth. The depth of water in the central constriction is 7 feet, 
with deeper water on both sides, the maximum depth observed in the 
north-eastern portion of the loch being 20 feet, while the maximum 
depth of the loch (39 feet) occurs in the south-western portion, com- 
paratively near the western shore, where the Conalter burn flows in 
and the Downie burn flows out. The area of the lake-floor covered by 
less than 10 feet of water is about 15 acres, or 39 per cent, of the total 
area of the loch; that covered by water between 10 and 20 feet in 
depth is about 14 acres, or 37 per cent. ; that covered by water between 
20 and 30 feet in depth is about 4 acres, or 12 per cent. ; and that 
covered by more than 30 feet of water is about 4 acres, or 12 per cent, 
of the entire area of the loch. Loch Monzievaird was surveyed on June 
8, 1903 ; its elevation above the sea was not determined by levelling, 
but it is evidently slightly under 200 feet since the 200-feet contour 
almost coincides with the shore-line. The outflow is controlled by a 
sluice, and on the date of the survey the water in the loch was very 
low. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch gave the following results : 



Surface ... 


68 '0 Fahr 


5 feet 
10 .. 


68-0 
60 '5 


15 


53 '0 


20 ,, 


51'0 


36 ,, ... 


47 '4 



This series shows a range of temperature from surface to bottom 
amounting to 20'6, there being a fall of 7-5 between 5 and 10 feet, 
and a similar fall between 10 and 15 feet a decrease of 15 in the 10 
feet of water, equal to l-5 per foot. 



THE FRESH- WATER LOCHS OF SCOTLAND. 121 

Loch Benachally (see Plate XXXIII.). Loch Benachally, a good 
trout loch in the Forest of Clunie, is used by the Blairgowrie Corpora- 
tion as the source of the town's water-supply. It flows by the Lornty 
burn into the river Ericht, which further on joins the river Isla. Its 
shores are of shingle and stones, except at the north-western corner, 
where the material brought down by the Craigsheal burn has formed 
an extensive flat covered with short weeds. This flat was dry at the 
time of the survey, the water in the loch being very low. It is sur- 
rounded by low hills covered with heather and grass. It is almost 
triangular in outline, the base towards the north-west and the apex 
pointing south-east, and is over a mile in length, with a maximum 
breadth of over half a mile, the mean breadth being about a quarter of 
a mile, or 23 per cent, of the length. Its waters cover an area of about 
163 acres, or a quarter of a square mile, and it drains an area of over 
3 square miles an area 12 times greater than the area of the loch. 
About 60 soundings were taken, the maximum depth observed being 
64 feet. The volume of water contained in the loch is estimated at 
177,566,000 cubic feet, and the mean depth at 25 feet, or 39 per 
cent, of the maximum depth. The length of the loch is 87 times the 
maximum depth, and 220 times the mean depth. Loch Benachally 
forms a simple basin, the bottom sloping more or less regularly on all 
sides down to the deepest part, which is approximately centrally placed. 
The slope of the bottom is in some places rather steep for instance, off 
the northern shore near the north-western angle, and off the southern 
shore near the middle, where soundings of 22 feet were taken about 60 
feet from the shore, giving a gradient in each case of 1 in 2'7. The 
loch is on the whole comparatively deep, very few of the soundings 
being under 10 feet. The area of the lake-floor covered by less than 
25 feet of water is about 91 acres, or 56 per cent, of the entire area of 
the loch; that covered by water between 25 and 50 feet in depth is 
about 58 acres, or 36 per cent. ; and that covered by more than 50 feet 
of water is about 13 acres, or 8 per cent, of the total area of the loch. 
Loch Benachally was surveyed on June 3, 1903, and the elevation of 
the surface of the water was determined, by levelling from bench-mark, 
as being 1004'9 feet above sea-level. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch gave the following results : 

Surface 57"2Fahr. 

10 feet 55-8 ,, 

15 54-3 

20 49-0 

*' 47'4 , 

*> , 47 -2 

><> 47-0 

, 46'8 



122 BATHYMETRICAL SURVEY OF 

This series shows a range of temperature throughout the 60 feet of 
water amounting to 10'4, the greatest fall being one of 5-3 between 
15 and 20 feet. 

Loch Shechernich (see Plate XXXIII.). Loch Shechernich (or 
Bainie), a small loch in Glenshee, situated amid fine mountain scenery, 
is a good trout loch, but strictly preserved. It flows by the Allt Mor 
into Shee water, thence by the Black water into the river Ericht, a 
tributary of the river Isla. Its shores are low and peaty, rising 
gradually to the surrounding heather-clad hills. Near the centre of 
the loch is an artificial island composed of small stones. Loch 
Shechernich trends in an east and west direction, and is nearly half a 
mile in length, and one-fifth of a mile in maximum breadth, the mean 
breadth being one-seventh of a mile, or 31 per cent, of the length. Its 
waters cover an area of about 42 acres, and it drains an area 16J times 
greater an area considerably over 1 square mile. Thirty soundings 
were taken, the maximum depth observed being 8 feet. The volume of 
water is estimated at 7,364,000 cubic feet, and the mean depth at 
4 feet, or 50 per cent, of the maximum depth. The bottom sinks 
gradually from the west towards the east end, being covered by less 
than 6 feet of water in the western half (to the west of the central 
island), while the greater portion of the eastern half is covered by more 
than 6 feet of water, the maximum depth of 8 feet having been observed 
in three places comparatively close to the east end. The area of the 
lake-floor covered by less than 5 feet of water is over 31 acres, or 75 per 
cent, of the entire area of the loch. Loch Shechernich was surveyed on 
the same day as Loch nan Eun, July 2, 1903. The elevation above the 
sea could not be ascertained, but from spot-levels it is probably about 
1330 feet. The water in the loch was about its lowest on the date 
of the survey, and apparently rises 1 to 2 feet higher. At 6 p.m. the 
temperature of the water at the surface and at a depth of 7 feet was in 
each case 59-2. 

Auchenchapel Loch (see Plate XXXIII.). Loch Auchenchapel (or 
Auchintaple), in Glenisla, near Inverharity, is an artificial loch made in 
1884, and flows by a short stream (Allt na Beinne) into the river Isla; 
it is a good trout loch, without pike. It trends in a north and south 
direction, and is over one-third of a mile in length, and over a quarter 
of a mile in maximum breadth, the mean breadth being over one- 
seventh of a mile, or 40 per cent, of the length. Its waters cover an 
area of about 35 acres, and it drains an area 5J times greater an area 
of one-third of a square mile. Over 40 soundings were taken, the 
maximum depth observed being 17 feet. The volume of water con- 
tained in the loch is estimated at 12,669,000 cubic feet, and the mean 
depth at 8 feet, or 49 per cent, of the maximum depth. Auchenchapel 



THE FRESH- WATER LOCHS OF SCOTLAND. 123 

Loch is irregular in outline, and the conformation of the bottom is also 
irregular, shallow water extending out into the loch in some places, 
while in other places comparatively deep water approaches close to the 
shore. The maximum depth of 17 feet was observed near the southern 
end of the loch, and a sounding of 15 feet was taken near the centre of 
the wide portion of the loch, in close proximity to a sounding of 5 feet. 
The diversity in the soundings gives a sinuous character to the 10-feet 
contour-line. The area of the lake-floor covered by less than 10 feet of 
water is about 22 acres, or 62 per cent, of the total area of the loch. 
The loch was surveyed on July 3, 1903, but the elevation above the sea 
could not be determined. The water rises about 2 feet above, and 
falls about 1 foot below, the level on the date of the survey ; there is a 
sluice at the outflow, but it was out of order and disused at the time of 
the survey. Temperatures taken at 10 a.m. in the position of the 
deepest sounding gave 58'0 at the surface and 57'5 at a depth of 
16 feet. 

Loch of Lintrathen (see Plate XXXIII.). The Loch of Lintrathen, 
from which Dundee draws its water-supply, has been raised in level to 
the extent of 22 feet in connection therewith; the water in the loch 
was 14 inches below the overflow on the date of the survey, so that the 
20-feet contour-line would show approximately the size and position of 
the original loch. It receives the drainage from a large tract of the 
hilly country to the north, and it flows by the Melgam water into the 
river Isla. It is surrounded by gently sloping cultivated ground or 
woods, with gravelly margin, except in the north-western angle of the 
loch, where the Melgam water and Inzion burn enter, which is shallow 
and obstructed by weeds. It is nearly 1J miles in length from south- 
west to north-east, with a maximum breadth of three-quarters of a 
mile, the mean breadth being nearly half a mile, or 33 per cent, of the 
length. Its waters cover an area of nearly 400 acres, or considerably 
more than half a square mile, and it drains an area 47 times greater, 
or nearly 29 square miles. Nearly 120 soundings were taken, the 
maximum depth observed being 70 feet. The volume of water con- 
tained in the loch is estimated at 405,207,000 cubic feet, and the 
mean depth at 23 J feet, or 34 per cent, of the maximum depth. The 
length of the loch is 104 times the maximum depth, and 311 times the 
mean depth. The Loch of Lintrathen forms a simple basin, the bottom 
sloping down, with few irregularities, to the deepest part, which is 
situated in the wide south-western portion of the loch. The maximum 
depth of 70 feet was observed to the north of Loch Craigs, considerably 
nearer the southern than the northern shore, and the slope of the 
bottom off Loch Craigs is evidently very steep, a sounding of 26 feet 
having been taken close to the shore. The line of soundings taken 
northwards from Loch Craigs shows a slight rise of the bottom towards 



124 BATHYMETRICAL SURVEY OF 

the centre of the loch, where depths of 54 to 57 feet were found, with 
depths exceeding 60 feet to the north and south. The northern portion 
of the loch, beyond the narrows at Balnakeilly, is comparatively 
shallow. The area of the lake-floor covered by less than 25 feet of 
water is about 260 acres, or 66 per cent, of the total area of the loch; 
that covered by water between 25 and 50 feet in depth is nearly 100 
acres, or 24 per cent. ; and that covered by more than 50 feet of water 
is over 40 acres, or 10 per cent, of the entire area of the loch. It was 
surveyed on June 25, 1903, and the height of the surface of the water 
above the sea was determined, by levelling from bench-marks, as being 
674-6 feet. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch gave the following results : 

Surface 55'5 Fahr. 

10 feet 55-2 

25 54-0 

50 52-5 

55 50'8 ,, 

60 48-2 

65 ... 48-0 

This series shows a range of temperature from surface to bottom of 
7'5, the greatest fall being one of 2-6 between 55 and 60 feet. 

Loch of For far (see Plate XXXIII.). The Loch of Forfar lies 
immediately to the west of the town of Forfar, surrounded by cul- 
tivated fields. It flows by the Dean water into the river Isla, the 
outflow being a broad ditch with no perceptible current on the date of 
the survey, the water in the loch being very low. It contains pike, 
perch, and trout. It trends almost east and west, and is over a mile in 
length, with a maximum breadth of nearly a quarter of a mile, the 
mean breadth being about one-seventh of a mile, or 14 per cent, of the 
length. Its waters cover an area of about 103 acres, or one-sixth of a 
square mile, and it drains an area 14 times greater an area of over 
2 square miles. Over 60 soundings were taken, the maximum depth 
observed being 29 feet. The volume of water is estimated at 51,232,000 
cubic feet, and the mean depth at 11 J feet, or 39 per cent, of the 
maximum depth. The length of the loch is 195 times the maximum 
depth and 494 times the mean depth. The Loch of Forfar is peculiar 
in conformation, due to the peninsula of Queen Margaret's inch jutting 
out into the loch about midway along the northern shore. From the 
extremity of Queen Margaret's inch a submerged causeway runs out, 
on which depths of 1, 2, and 3 feet were found. The deepest water in 
the loch lies to the north and west of the inch and causeway, approach- 
ing quite close to the end of the causeway, where a depth of 28 feet 
was recorded, the maximum depth of 29 feet being found a few hundred 



THE FRESH- WATER LOCHS OF SCOTLAND. 125 

feet to the west. To the south and east of the inch depths of 22, 25, 
and 26 feet were found, separated from the deep water to the west by 
depths of 13 to 16 feet. The 10-feet basin is a continuous area, nearly 
three-quarters of a mile in length, following approximately the outline 
of the central portion of the loch, the two ends of the loch being com- 
paratively shallow, and weeds are abundant off the northern shore at 
the east end. The area of the lake-floor covered by less than 10 feet 
of water is about 56 acres, or 54 per cent, of the total area of the loch ; 
that covered by water between 10 and 25 feet in depth is about 39 
acres, or 38 per cent. ; and that covered by more than 25 feet of water 
is about 8 acres, or 8 per cent, of the entire area of the loch. The Loch 
of Forfar was surveyed on June 26, 1903, and its elevation above the 
sea was determined, by levelling from bench-mark, as being 166-3 feet; 
when levelled by the officers of the Ordnance Survey in 1861, the 
elevation was found to be 170'5 feet above sea-level. 

.Temperature Observations, Temperatures taken in the deepest part 
of the loch gave the following results : 

Surface 58'9 Fahr. 

10 feet 58 3 ,, 

15 57'7 

20 , ... 56-0 

27 ,, 56-0 

This series shows a range of temperature from surface to bottom of only 
2-9, the greatest fall being one of l-7 between 15 and 20 feet. 



The particulars regarding the different lochs within the Tay basin 
are collected together in the table on next page for convenience of 
reference and comparison. Where the elevation above the sea has 
not been determined by levelling from bench-mark, the approximate 
elevation has, where possible, been indicated within brackets. 

From this table it will be seen that in the 59 lochs under con- 
sideration 6850 soundings were taken, and that the aggregate area of 
the water surface is about 40 square miles, so that the average number 
of soundings per square mile of surface is 172. The aggregate volume 
of water contained in the lochs is estimated at 151,353 millions of 
cubic feet. The area drained by these lochs is 1100 square miles, or 
27J times the area of the lochs. 



126 



BATHYMETRICAL SURVEY OF 



Il 



s . 






I I I I IQ 

t- 6 o o o o 



^-i 1-- -H 00 O5 CD CO >C 



pa 5 

111 



gciMisoflpo^cocotrOt^^Hi-i^OGCOsot-coQ^coeo 
S -^RJ" 1 ^^^^^^??^2"'-^^S ao 2 



O CD OJ <N ^ >C l^ CO SC ^ ( ^ >C -O 'N >O ^O r CC lr < O O QO QO C<l 
l^ 'N '1 t O C^ X ^ * >^ X O -f O X 'M O 't X t CC * >O ^N ^ 



Oc:'CC^ioooo:'O^o^ooO l 7<ioocCr-<^'rjic 
85 ^ d >o tj >-i 55 w -* S 2S ^ ^ MJ -^ rt 



INI 



UO(N^7^MTj<W^F7H^r^r^CqCpC01^-'N--l^-(f^Hr^-lF-I^HpOqp 
-,0006000060000660 



^HOOOOrHOOO-HOOOOO-HOOOOOOOOOO 



' i^CO'M-^OOOOOOOOOO 



Ivi* 

a s 



OOOOOOOi 

cc o ^ o <N t~- cc oo x cc 01 o i> * 

US ^ X ^ ^ i^ ^ ' i < CO H H -C ^ '^T 



p ?CCC 

p o : : ;oi> 

5 OS Th OS 



M... 



HOW 






THE FRESH-WATER LOCHS OF SCOTLAND. 



127 



r^ i i i i -* r: <e 71 71 

re re 71 re >7 71 



- 
^ ^i x x 5i re ?t r: S o O - oo oo ^H 

' 






~ : re c re i^ 17 71 7^1 re 71 vr 

gg^ss^^^^^^sss^i 



ie 

C ^ -r "^ '- 71 - ^ 71 - -- '-: X - I- 



: X C i- 



i M T ^ . t M . . ^ . 

cccocoooo 



cocce-c^cccoooo 



re re r: ^ re 7J -t re -t- re x re r: 71 71 c r: c i^ C 71 c: c re t^ cc 
^ 71 re i >7 >7 -c 17 x i - re re -? 71 re re "7 re x re 17 ^- re ir - 17 re Tf -^5 



^ c" '" r r:= "~ : P "-r T* 1 l * '.^ ?' "-r ^ ? ? '" ^ "^x 1 ^"^ ' ^ "^ ^ ^ 
: >r; i^ re tr: r-^ r^ i Hq3OOO5(Noc -+ t ^ x ft 'M S -t 55 * i 

-i : : : ~ : 



i'O.j-^.cj cs c : 



128 BATHYMETRICAL SURVEY OF 



NOTES ON THE GEOLOGY OF THE TAY BASIN. 

By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. With 
Geological Map (Plate XXXIV.). Published by permission of the 
Director of H.M. Geological Survey. 

The Tay basin may be divided geologically into two parts, the 
boundary between the two being denned by the great fault along the 
Highland border which runs from Glen Artney, by Crieff , Murthly, and 
Blairgowrie, towards Cortachy and Stonehaven. The area north-west 
of this line is mainly occupied by the metamorphic rocks of the Eastern 
Highlands, which are pierced by masses of granite, diorite, and other 
igneous intrusions, the latter being of special importance in connection 
with the history of the glaciation of the region. In the western part of 
the metamorphic area, on the lofty peaks of the Black Mount forest, 
there is a remnant of the contemporaneous volcanic rocks of Lower Old 
Red Sandstone Age, which are so prominently developed in the Lome 
plateau. The tract, south-east of the Highland fault, embraces the 
lower and smaller portion of the Tay basin. With the exception of a 
small patch of Carboniferous strata near Bridge of Earn, the whole of 
this tract is occupied by rocks of Old Red Sandstone age. 

In connection with the Lake Survey, the area north-west of the 
Highland fault is of special interest, as it includes most of the lochs 
which have been sounded by the staff. The metamorphic rocks which 
floor the greater part of this tract are bounded on their south-east 
margin, for a considerable distance, by the great dislocation along the 
Highland border. Indeed, the fault-line in places gives rise to a 
prominent feature, and the change, in the geological formations on 
either side, is indicated by a marked difference in the topography. The 
age of the metamorphic rocks of the Eastern Highlands has not 
been definitely fixed, and the original sequence of deposition is still 
uncertain, but they have been arranged in certain groups, which appear 
in a definite order as the observer proceeds northwards from the border 
fault. 

Apart from the crystalline schists termed the " Moine Series " by 
the Geological Survey, which occur in the northern part of the area, 
the groups of metamorphic strata met with in the Tay basin are given 
in the subjoined table : 

11. Quartzite and quartz-schist with pebbly conglomerate and 

boulder bed. 
10. Blair Atholl limestone. 

9. Black schist with thin limestone bands. 

8. Calc-sericite schists and phyllites. 






THE FRESH-WATER LOCHS OF SCOTLAND. 129 

7. Garnetiferous mica-schists. 

6. Loch Tay limestone. 

5. Garnetiferous mica-schists of Pitlochry. 

4. Hornblende-schists of clastic origin and epidote-chlorite schists 

(Green Beds). 

3. Schistose grits (Ben Ledi grits and schists). 

2. Dunkeld slates. 

1. Schistose grits next the Highland fault. 

The members of the metamorphic series have been injected by sheets 
and bosses of acid and basic igneous materials, which have shared in 
the folding and schistosity of the altered sediments into which they 
have been intruded. 

The distribution of these various groups of altered sedimentary 
strata, and the intrusive sheets of basic igneous material (epidiorite 
and hornblende-schist), have had an important influence in determining 
the trend of the tributary valleys and their surface features. The sub- 
divisions given in the above table form sub-parallel belts crossing the 
basin in an east-north-east and west-south-west direction, the outcrops 
of which have been affected by several powerful faults, to be referred to 
presently. 

Beginning at the Highland border, we find immediately to the north 
of the marginal fault a narrow band of schistose grits, extending from 
the river Almond to Birnam wood on the Tay, which may represent the 
Leny and Aberfoil grit of the Callander district. Next in order comes 
a zone of slate, traceable almost continuously from the forest of Glen 
Artney, by Comrie, to a point south of Dunkeld, where it is exposed 
in various quarries. The Ben Ledi grits and schists, which, as they are 
followed northwards, become more schistose and highly crystalline, 
form a belt several miles in width, extending across the basin from the 
heights round Loch Earn, north-eastwards by the Almond, Strath 
Bran, and the Tay between Birnam Hill and Logierait, and onwards by 
Strath Ardle to Kirkton of Glen Isla. Over much of the area where 
the metamorphism is not highly developed the schistose grits of this 
group give rise to prominent rock features. 

The Ben Ledi grits are followed northwards by an important zone 
of epidote-chlorite schists (Green Beds), which, in their ultimate stage 
of alteration, merge into hornblende-schists that are almost indis- 
tinguishable from rocks of this type of igneous origin. They are usually 
associated with intrusive sheets of epidiorite that pass into hornblende- 
schists, the latter sharing in the folding and schistosity that have 
affected the Green Beds. Like the members of this zone in the 
Callander region, these epidote-chlorite schists and accompanying sills 
of epidiorite form prominent rock features in the landscape, which 
have more successfully resisted glacial erosion than the overlying zone of 

K 



130 BATHYMETRICAL SURVEY OF 

garnetiferous mica-schist. On both sides of the valley of the Tay at 
Aberfeldy these rocks may be studied, and they appear on the moor- 
land between the Tay and Strath Ardle, and eastwards by Kirkton of 
Glen Isla, either as isolated patches in the form of outliers, or as more 
or less continuous outcrops. Again, towards the south-west, the Green 
Beds reappear at intervals on the heights between Loch Tay and Loch 
Earn till they are abruptly truncated by the Loch Tay fault. 

One of the best-defined zones in the metamorphic series of the 
Eastern Highlands is that of the Loch Tay limestone, with its overlying 
and underlying garnetiferous mica-schists. In the Tay basin the 
members of these groups (5, 6, 7) usually indicate a stage of high 
metamorphism, the beds being easily eroded by surface agencies. Save 
where deflected by powerful faults, their outcrops are traceable almost 
across the basin. From Glen Fernate, at the head of Strath Ardle, the 
Loch Tay limestone has been followed south-westwards, by Pitlochry, 
along the north slope of the Tay valley at Aberfeldy, to the heights 
overlooking Fortingal, where the outcrop has been deflected by the 
Loch Tay fault. West of this line of disruption the limestone reappears, 
about 4 miles further south, on both sides of Loch Tay (see geological 
map), whence it can be traced westwards up Glen Dochart and across 
Strath Fillan almost to the slopes of Ben Lui, at the south-west 
margin of the Tay basin. Owing to folding, the Loch Tay limestone 
and its associated strata reappear to the north of the line of outcrop 
just indicated, as, for instance, in Glen Lyon and in the valley of the 
Lochay north-west of Killin; and to the south of this line, it is met 
with at Lochearnhead and on the Braes of Balquhidder. An important 
feature connected with this limestone is the frequent occurrence of a 
massive sill of epidiorite in conjunction with it. 

Still further north the sub-divisions just described are succeeded by 
calc-sericite schists, phyllites, and black schists with thin lenticular 
bands of limestone (groups 8, 9), which present lithological characters 
that are, as a rule, readily identified. The trend of the outcrop of these 
zones has been affected by the north-east and south-west faults which 
traverse the basin, and the black schist spreads over a broad area, in 
certain localities, by means of sharp isoclinal folds. Taking first the 
most southerly outcrop of the calc-sericite schist, phyllites, and black 
schist, they are traceable from Ben Vrackie south-west by Faskally on 
the Tay, to the Loch Tay fault north of Fortingal. West of this line 
of disruption, they have been followed from Glen Lyon, by Ben Lawers, 
and across Glen Lochay to the heights above Glen Dochart, where they 
terminate in a synclinal fold of the underlying garnetiferous mica- 
schists associated with the Loch Tay limestone. Still further west they 
reappear and form a broad outcrop stretching from the upper part 
of Glen Lyon in a south-south-west direction towards Tyndrum, where 
they are again interrupted by a north-east and south-west fault (see 
geological map). 



THE FRESH-WATER LOCHS OF SCOTLAND. 131 

The Blair Atholl limestone has an important development in the 
neighbourhood of Blair Atholl, and up the valley of the Tilt towards 
the limit of the basin. Sharing in all the folds of the associated 
phyllites and black schists (group 9), its outcrop is irregular and 
involved. Where these zones appear, in the Tilt, in the Tay, and 
Strath Tummel, they generally give rise to softer outlines than the 
quartzite which apparently overlies them. 

The Perthshire quartzite (group 11) is, perhaps, the most striking 
geological sub-division in the metamorphic series of the Eastern 
Highlands, from its greater durability and the lofty mountains to which 
it has given rise. Along its northern margin the rock is more or less 
coarse-grained, due to the presence of pebbles of quartz and felspar, 
but this band is repeatedly brought to the surface by means of folding. 
An interesting feature of this group is the presence of a conglomerate 
or boulder bed with rounded blocks of granite, foreign to the area, the 
matrix of which seems to vary with the rock in contact with it. Some- 
times appearing as lenticular or boat-shaped masses surrounded by 
black schists, phyllite, or limestone, and again as narrow belts traceable 
for several miles, the quartzite is always one of the dominant features 
of the landscape, occasionally forming lofty peaks, as in Ben-y-Ghlo 
and Schichallion. 

In addition to the sub-divisions of the metamorphic rocks of the 
Eastern Highlands which have just been described, there is a group of 
crystalline schists termed the " Moine series " by the Geological 
Survey, which have a wide distribution in the north-west part of the 
Tay basin. Their lithological characters are remarkably persistent over 
wide areas. Consisting mainly of quartzose granulitic schists or fine- 
grained gneisses with bands of mica-schist, they represent without 
doubt a highly altered series of sediments, the original clastic grains 
of which have been destroyed. They form nearly the whole of the area 
north of Loch Rannoch, up Glen Garry, and northward of Glen Tilt. 

Reference has already been made to the intrusive sheets of basic 
igneous rock which appear in association with the Green Beds and Loch 
Tay limestone, but others occur in connection with the zones of calc- 
sericite schist and black schist. Perhaps the most remarkable example 
of the latter is the mass of epidiorite and hornblende-schist on Ben 
Vrackie north of Pitlochry, where the altered sediments have been 
deflected and bent round the laccolitic intrusion. 

The acid igneous rocks which were injected into the sedimentary 
series, before the folding and development of schistosity in the latter, 
are best represented by the foliated granite of Ben Vuroch, north-east 
of Ben Vrackie. On the north-west slope of that mountain, the 
sediments, which still retain their original bedding, have undergone 
contact alteration, the calcareous shales having been converted into 
calc-silicate hornfels. 



132 BATHYMETRICAL SURVEY OF 

In the central part of the metamorphic area there is a well-defined 
line extending from Ben Vrackie south-west by Ben Lawers to Glen 
Lochay, which marks the axis of a fan-shaped arrangement of the 
folding of the strata. Along this line the axial planes of the folds are 
vertical, and on either side they are inclined towards the centre of the 
fan. Hence on the south-east side of this central axis there is a 
remarkably persistent dip of the folds towards the north-west, while 
on the north-west side the general inclination is towards the south-east. 
A fine example of the latter is to be found in the river Garry, where 
between Blair Atholl and Dalnaspidal the granulitic schists of the 
Moine series dip persistently towards the south-east for a distance 
of about 15 miles, and yet it is highly probable that the same 
bands are repeated indefinitely by means of folding. This remarkable 
reduplication of the strata can be clearly demonstrated in the case of 
the black schist, limestone, and quartzite groups, where the lithological 
types are clearly differentiated from each other. For a distance of 
6 miles across the strike, between Ben Vrackie and Glen Tilt, these 
groups constantly reappear, the sill of garnetiferous hornblende-schist 
being indefinitely repeated with the black schist. 

Reference has already been made to the system of north-east and 
south-west dislocations which traverse the metamorphic area. Of these, 
apparently the most powerful is the Loch Tay fault, which has been 
traced from near Blair Atholl, across Loch Tay, Loch Earn, and Loch 
Lubnaig, till it is truncated by the fault along the Highland border at 
Aberfoil. Further west, and roughly parallel with the foregoing, comes 
the line of disruption which extends from Loch Garry across Loch 
Rannoch and the valleys of the Lyon, the Lochay, and the Dochart 
towards the Braes of Balquhidder. Again, from Tyndrum another 
dislocation has been followed north-east by Loch Lyon and the west 
margin of Loch Rannoch in the direction of Loch Ericht. Finally, in 
the north-west part of the basin there is a line of fracture running along 
Loch Ericht and Loch Laidon, which is roughly parallel with the Loch 
Tay fault. In the case of the Loch Tay, th Loch Garry, and the Loch 
Lyon dislocations, the downthrow has been on their western side; in 
other words, on that side the outcrops of the sedimentary bands and 
epidiorite sills have been shifted further to the south by each fault in 
turn. 

Within the metamorphic area, as already indicated, there are 
various masses of igneous rock which are later than the folding and 
foliation of the crystalline schists, and have been referred to the newer 
granite intrusions of the Highlands. Of these, the most important is 
the large mass of diorite on the Moor of Rannoch, which stretches 
northwards to Loch Ericht and west towards Loch Treig, boulders of 
which have been carried far during the glaciation of the region. Other 
masses appear on both sides of Loch Ericht, in Glen Tilt, on the lofty 



THE FRESH -WATER LOCHS OF SCOTLAND. 133 

plateau north of that valley, and far to the south in Glen Lednoch 
between Comrie and Loch Tay. Several of these igneous intrusions 
consist partly of diorite and partly of granite, the more basic type being 
erupted prior to the more acid. 

At the western margin of the basin on the lofty peaks of the Black 
Mount forest there is a terraced plateau of contemporaneous igneous 
rocks of Lower Old Red Sandstone age, pointing to the former 
extension of this volcanic series, the distribution of which is of 
importance in connection with the glaciation. These are pierced by 
plutonic rocks (granite), which have produced a certain amount of 
contact alteration in the lavas. 

In the lower part of the basin of the Tay, which is almost wholly 
occupied by Old Red Sandstone, both the lower and upper divisions of 
that system are represented. The Lower Old Red Sandstone has by 
far the greater development, being divisible into a lower volcanic series 
and an overlying group of sandstones, conglomerates, and marls. Two 
great flexures cross the basin in a north-east and south-west direction, 
roughly parallel with the fault along the Highland border. One of 
these flexures forms a broad arch, exposing a great series of contem- 
poraneous volcanic rocks in the Ochils and the Sidlaws ; the other forms 
a great trough, in line with the valley of Strathmore, containing the 
highest members of this division in the basin of the Tay. The anti- 
clinal fold is prolonged far to the north-east into Forfarshire and 
Kiiicardineshire, where sandstones and flags appear in the crest of the 
arch. In the Ochils the total thickness of lavas, tuffs, and agglomerates 
in the north limb of the fold is about 6000 feet, and they were probably 
deposited on a gradually sinking area ; nevertheless, some of the volcanic 
cones may have ultimately appeared above the level of the water and 
become subaerial. Rising out from underneath the overlying sand- 
stones and marls, along the Highland border, the volcanic series again 
appears, though in a very attenuated form, consisting of andesitic lavas, 
which are associated with coarse conglomerates containing pebbles of 
volcanic rocks. Indeed, the lavas, conglomerates, and sandstones occur 
on the north side of the fault at Blairgowrie, and again at Crieff, where 
they rest unconformably on the metamorphic rocks. The broad tract 
of low ground between the Sidlaws and the Highland border has been 
carved out of the softer sandstones and marls overlying the volcanic 
series. The river Isla, when it enters the area occupied by this 
overlying sedimentary series, is deflected towards the south-west till it 
joins the Tay. 

The long interval which elapsed between the Lower and Upper Old 
Red Sandstone periods was marked by great denudation of the members 
of the lower division of that system. The strata were thrown into 
anticlinal and synclinal folds, the axes of which are roughly parallel 
with the trend of the fault along the Highland border. And further, 



134 BATHYMETRICAL SURVEY OF 

along the crest of the arch, the higher members of the lower division 
were worn away, and the volcanic rocks were laid tare, before the 
Upper Old Red Sandstone was deposited. The members of the upper 
division occur near Bridge of Earn, and extend beneath the estuary of 
the Tay and the Carse of Gowrie to near Dundee. Between Forgan- 
denny and Bridge of Earn, the basement beds are found resting 
unconformably on the denuded Lower Old Red Sandstone volcanic 
rocks, where fragments of the latter occur in the breccias. On both 
sides of the estuary of the Tay, however, the Upper Old Red Sandstone 
is brought into conjunction with the volcanic series of the lower division 
by two parallel faults. The members of the upper division are 
composed mainly of friable brick-red sandstones and marls, which have 
yielded near Errol fine specimens of the genera of fishes characteristic 
of this division. 

Reference has already been made to the fact that a small patch of 
Carboniferous rocks appears about half a mile to the south of Bridge of 
Earn, which are brought into conjunction with the Lower Old Red 
volcanic rocks to the south by means of a fault. The strata consist of 
blue clays and shales, sandstones, and calcareous bands belonging to 
the Cementstone group. Small though it be, this remnant is of great 
importance in proving the former extension of the Carboniferous rocks 
over the lower part of the Tay basin, from which it has been almost 
wholly removed by denudation. 

The existing valley system of the basin of the Tay furnishes 
admirable examples of the influence of geological structure in 
determining the direction of the water drainage. The upper part of 
the Tay itself, and many of the tributaries within the metamorphic 
area, flow approximately in the direction of the strike of the crystalline 
schists. The massive Ben Ledi grits, the Green Beds, the sills of 
epidiorite and hornblende-schist, and the Perthshire quartzite have 
each had a powerful influence in the development of the prominent rock 
features of the region. Where these occur in association with zones of 
mica-schist and phyllite, they have more successfully resisted erosive 
action, and have given rise to rocky barriers or precipitous escarpments, 
thereby contributing to the formation of gorges, and in some cases of 
rock-basins. 

The evidence relating to the glaciation of the Tay basin leads to the 
conclusion that, during the climax of the Ice age, the region must have 
been covered with one continuous sheet of ice, the movement of which 
must to some extent have been independent of the existing valley 
system. Where the rocks have been able to retain the striae, the latter 
have, been found up to elevations of 3000 feet, showing that the highest 
mountains were over-ridden by the ice. This stage was followed bv 

*/ o J 

a period of confluent glaciers, when the ice streamed over passes 
connecting adjoining valleys, leaving in its track lines of moraines. 



THE FRESH- WATER LOCHS OF SCOTLAND. 135 

Finally, there is the phase of corrie glaciers, when the glacial detritus 
was borne for no great distance from the local centres of dispersion. 

During the maximum glaciation, the ice-shed lay round the north- 
west margin of the Tay basin, from the mountains beyond Rannoch 
Moor, by Ben Alder west of Loch Ericht, eastwards to the watershed 
separating Glen Garry from the tributaries of the Spey and the Dee. 

Beginning in the western part of the basin, with the lofty watershed 
between the head of Glen Lyon and Glen Lochay, in the Mamlorn 
forest, striae are found at intervals along this ridge for a distance of 
3 miles, at elevations which in some cases vary from 2700 to 3000 feet, 
trending E. 20 to 30 S. Further east, about 3 miles north of Killin, 
on Creag-iia-Caillich at a height of 2250 feet, the direction is about 
south-south-east. Again, to the west of Ben Lawers, the ice-markings 
point S. 40 E. about the 2000-feet level. Proceeding northwards to 
the dividing line between Glen Lyon and Strath Tummel, the evidence 
is no less remarkable, for on Schichallion, at an elevation of 3000 feet, 
the trend is E. 30 S. Still further north, on Beinn a' Chuallaich a 
high mountain between Glen Erichdie and Kinloch Rannoch -the 
striae point S. 30 E. at a height of 2700 feet. Again, on Ben Vrackie, 
about 3 miles north of Pitlochry -a mountain which is glaciated to 
the top the trend is east-south-east. Similar conclusive evidence 
is obtained on the dividing ridge that stretches eastwards from 
Schichallion towards Pitlochry and separates Strath Tummel from 
the upper course of the Tay between Aberfeldy and Logierait. Part 
of this ridge is composed of the Perthshire quartzite, the glaciated 
surfaces of which show finely preserved striae, the direction varying 
from E. 20 S. to E. 45 S. On one of the prominent peaks of this 
ridge Ben Eagach south of Loch Tummel, ice-markings are found on 
the top at a height of 2250 feet, which point E. 35 S. Further south, 
on the dividing ridge between Strath Bran and the valley of the 
Almond, on Meall nan Caoraich, the direction is E. 30 S., close to the 
2000-feet contour-line. Additional instances might be given from the 
mountainous region within the metamorphic area, but the above 
examples establish the conclusion that during the maximum glaciation 
there must have been a movement of the mer de glace independent of 
the valley system in an east-south-east or south-easterly direction. 

During the great extension of the ice, on the broad plateau of the 
Moor of Rannoch the ice seems to have radiated partly towards the 
east-south-east or south-east, and partly towards the south-west in 
the direction of the Tulla and Glen Orchy (see geological map). 

The evidence obtained from the dispersal of the boulders is no less 
remarkable, for in some cases they have been carried far from their 
parent source, and over lofty cols. The boulders of diorite or horn- 
blendic granite from the Moor of Rannoch have been found in Strath 
Tummel, in Glen Lyon, in Strath Fillan, in Strath Tay, and across the 



136 BATHYMETRICAL SURVEY OF 

watershed into Glen Almond. Again, all along Strath Fillan, Loch 
Tay, and Strath Tay, boulders of the Perthshire quartzite, black 
schist, limestone, and calc-sericite schist have been carried several miles 
to the south of the various belts from which they were derived. Of 
course, in many of these instances, the boulders may have been dis- 
tributed during the later glaciation. On the slopes of Ben More (3843 
feet), which is composed of grits of the Ben Ledi group, blocks of calc- 
sericite schist occur that have been carried from the hills to the 
north-north-west in the direction of the. Mamlorn forest. Confirmatory 
evidence is furnished by the dispersal of the stones in the boulder clay 
a deposit formed during the great extension of the ice. Within the 
metamorphic area, sections of boulder clay occur up the Tay valley as 
far as Loch Tay, in the valleys of the Tummel and the Garry as far as 
Struan, and in Strath Bran from Amulree to Dunkeld. Outlying 
patches are found also at the east end of Loch Rannoch and round 
Loch Tummel. 

After the stage of the great ice-sheet, there followed a period of 
confluent glaciers when the ice was still thick enough to stream over 
passes connecting adjoining valleys, as, for instance, over some of the 
cols between Glen Lyon and Glen Lochay, between Glen Lyon and Loch 
Tay, and between Glen Lochay and Glen Dochart, between the upper 
course of the Tay and Strath Bran, and between Loch Tay and Glen 
Almond. Again, the glacier which moved eastward from the high 
mountains in Black Mount forest and at the head of Glen Coe and Glen 
Etive was deflected southwards, part of it flowing into Glen Orchy, and 
part into Strath Fillan. The numerous groups of moraines, frequently 
showing a terraced arrangement along the hill slopes, indicate the great 
development of the later glaciation. Fine examples of the local 
dispersion of moraines are to be found in the neighbourhood of the 
Black Mount forest and the mountains round the head of Glen Etive 
and Glen Coe. The debris of Old Red Sandstone volcanic rocks have 
been traced in the moraines eastwards from the Black Mount forest to 
the drift-covered plateau at Loch Ba. 

Within the Tay basin by far the larger number of the lochs lie in 
the midst of drift deposits, most of which are of 110 great size, and are 
comparatively shallow. In the southern part of the Moor of Rannoch, 
along the river Ba and its tributaries, in Allt Lochain Ghaineamhaich, 
and on the drift plateau, about twenty-five lochs occur in the midst of 
morainic drifts. Numerous examples of this type occur in other parts 
of the basin. 

Again, several lochs, some of which are of considerable size, lie 
along lines of displacement, or fault-lines, for which reason they need 
not now be discussed. For example, Loch Ericht and Loch Laidon are 
situated on one line of disruption which has been traced over a con- 
siderable distance in the eastern Highlands. Loch Garry, at the head 






THE FRESH- WATER LOCHS OF SCOTLAND. 137 

of Glen Garry, and Loch Lyon, near the head of Glen Lyon, likewise 
occur along lines of fault. In each of these cases, the long axis of the 
loch coincides with the course of a more or less powerful dislocation, 
which has been traced for miles. 

The following instances might be discussed in relation to the 
question of the glacial origin of rock basins : Loch Rannoch, Loch 
Tummel, Loch Tay, Loch Earn, Loch lubhair, and Loch Dochart. Of 
these, the first four have been previously described by our colleague, 
Mr. J. S. Grant Wilson, in the Scottish Geographical Magazine for 
May, 1888, in connection with the soundings made by him in the 
course of the geological survey of the district. It is not necessary, 
therefore, to give in detail the evidence in support of the view that 
these lochs, with the exception of Loch Tay, have been eroded by ice- 
action. His soundings have been, as a rule, confirmed by Sir John 
Murray and his staff. 

Loch Raimoch is a fine instance of a rock basin, for though, at the 
lower end, the river Tummel, which issues from the loch, flows along 
an alluvial flat for a distance of 3 miles as far as Dun Alastair, a rocky 
barrier appears at the latter point in the river and on the hill slopes. 
Near the foot of the loch, on either side of the valley, there is a 
prominent mass of high ground, culminating in Schichallioii (3547 feet) 
and Beinn a' Chuallaich (2925 feet). The streams draining this high 
ground to the north and south have silted up the loch at the lower end, 
and have produced the long stretch of alluvium between Kinloch 
Rannoch and Dun Alastair. The longitudinal section of Loch Rannoch 
shows that the loch gradually deepens from the west margin towards 
the centre and lower end. The soundings further show that between 
the mouth of the Dall burn and the foot of the loch there are three 
small basins, each over 400 feet in depth. The deepest sounding 440 
feet is in the centre of the largest and most easterly of these three 
basins, and within 2 miles of Kinloch Rannoch. On referring to the 
geological map it will be seen that the Loch Garry fault crosses Loch 
Rannoch near Dall in a S.S.W. direction; and, notwithstanding the 
fact that the downthrow side of this fault is towards the west, yet the 
deepest sounding is found on the upthrow side. 

Loch Tummel is another typical example of a rock basin, the rocky 
barrier appearing in the stream and on the hill slopes at Allean House, 
about a mile below the mouth of the lake. For several miles down- 
stream, as far as Faskally, the Tummel cuts through solid rock, 
composed mainly of the Perthshire quartzite, with bands of black 
schist. This loch has had originally a greater extension westwards, 
for it has been silted up by alluvial matter deposited by the streams. 
It is about 2 miles long, and the soundings show that it forms three 
separate basins of no great depth, the deepest sounding of the western 
basin being 128 feet; of the central, 119 feet; of the eastern, 99 feet. 



138 BATHYMETRICAL SURVEY OF 

Where these slopes and barriers appear, streams enter the lake from 
the south, which have given rise to cones projecting for some distance 
into the loch. It is probable, however, that they may be formed partly 
of solid rock. Judging from the evidence round the sides of Loch 
Tummel, the floor of that loch consists mainly of black schist, with 
infolds of the lower part of the quartzite. 

Loch Earn may be described as the best instance of a typical rock 
basin within the catchment area of the Tay. Upwards of 6 miles long 
and about three-quarters of a mile broad, the soundings show that it 
is a simple basin. The deepest sounding 287 feet occurs about half- 
way down the loch. The Loch Tay fault crosses the lake about a mile 
from the upper or western end; and along its course there is a small 
basin, the greatest depth of which is 240 feet. West of this fault, the 
floor of the loch is composed of the Loch Tay limestone and the under- 
lying garnetif erous mica-schists ; east of it, for some distance, the lake 
lies obliquely across the strike of the schists overlying the Green Beds 
and the Green Beds themselves; while at the foot of the loch the Ben 
Ledi grits appear as a rocky barrier crossing the valley at St. Fillans. 

Lochs lubhair and Dochart may be cited as further instances of rock 
basins. Originally forming one sheet of water, they have been isolated 
by alluvial matter brought down by the stream that drains the great 
corrie west of Ben More. The deepest sounding of Loch lubhair 65 
feet is near the foot. Roches moutonnees appear in that lake, both 
about the middle and near the foot. Loch Dochart is being rapidly 
silted up; indeed, it must formerly have extended for 3 miles up the 
valley of Strath Fillan. The deepest sounding of Loch Dochart is 
11 feet. 

Further down Glen Dochart there is a strip of alluvium about 5 
miles long, between Luib station and Easter Lix, which may probably 
represent a silted-up rock basin. 

Loch Tay presents certain features which differentiate it from the 
rock basins already described. There is no rocky barrier close to the 
lake; the Loch Tay fault runs along the course of the lake for a 
distance of 5J miles from Ardeonaig to Stronfearnan ; the greatest 
depth, which is 508 feet, lies on the downthrow side of this dislocation ; 
and finally there is a basin 12 miles long, the whole of which is below 
the level of the sea. The first appearance of solid rock in the bed of the 
Tay is north of Grandtully castle, about 8 miles below the foot of the 
loch, where mica-schists appear, belonging to the group of the Ben 
Ledi grits. For a distance of 1J miles below this point to near 
Ballinluig village the river flows at intervals over rocky ledges. There 
can be no doubt that the deflection of the original valley of the Tay 
between Ardeonaig and Stronfearnan was due to the Loch Tay fault, 
whereby the Loch Tay limestone and associated schists on its western 
side were brought into conjunction with the intrusive igneous masses 



THE FRESH- WATER LOCHS OF SCOTLAND. 139 

of Tomnadashan and Beinn Bhreac. The soundings show that the 
deepest part of the basin, which is bounded by the 400-feet contour- 
line, lies along the course of this fault. Under these circumstances, 
Loch Tay cannot be regarded as a typical example of a rock basin. 

The other rock basins, however, seem to us to furnish strong 
evidence in support of the theory that they have been eroded by ice- 
action. 



BIOLOGY OF THE LOCHS OF THE TAY BASIN. 
By JAMES MURRAY. 

While it was not compatible with the bathymetrical work of the 
Lake Survey to study in detail the biology of the lochs, it has been 
customary to make collections of the plankton of each loch, a coarse and 
a fine net being used in each case. It is thus possible to compare only 
the biology of the open water of the different lochs. The number of 
species living in the open water is not very great, and does not vary 
in different lochs so much as might have been expected. The fauna of 
the shallower lochs is usually much richer than that of the deeper ones, 
owing to the occurrence in them of many species which in larger lochs 
would be confined to the shore region. Even thus limited, it is found 
that the lochs differ sufficiently from one another to render a com- 
parative review of them of much interest. Each loch has a distinct 
character, which, notwithstanding a considerable amount of seasonal 
variation, is pretty constant. 

A small number of animals and plants occur so constantly in the 
open water of all our lakes, large or small, that they mainly determine 
the character of the plankton of this pelagic region. They are so 
generally present that the absence of any one of them is occasion for 
remark. The most important of them are Diaptomus gracilis, Cyclops 
strenuus, Daplmia lacustris, Bosmina obtusirostris, the Rotifers 
('uuochilus (two species), Anurcea cochleare, and Notholca longispina, 
and the Diatom Asterionella gracillima. These are found at all seasons. 
In the summer, Holopedium, Leptodora, Bythotrephes, and Polyphemus 
are as generally distributed. 

Only less common are Asplanchna priodonta, Polyarthra platyptera, 
Pendinium tdbulatum, Ceratium Jiirundinella, Mallomonas. Some 
Desmids, mostly of the genus Staurastrum, but including also species of 
Mirrasterias, Xanthidium, and Closterium, are generally present. The 
Rotifers Floscularia pelagica and Notops pygmceus are of frequent 
occurrence. Although all of those species may be present in most of 
the lochs, the varying proportions in which they occur in the plankton 
give rise to great differences of character in the lochs. Other species of 



140 BATHYMETRICAL SURVEY OF 

Diaptomus, Daphnia, and Bosmina are occasionally found, but the 
species included in the preceding list are so much more common, that 
when the generic name only is mentioned it will be understood that 
the common species is referred to. 

This small association of animals and plants constitutes what may 
be called the lacustrine type of plankton. A not very dissimilar 
association is found in small ponds, but the species for the most part 
are different. The Diaptomus may be D. castor, the Daphnia D. pulex, 
the Bosmina B. cornuta; Rotifers and Algae will be more abundant and 
varied, and there will probably be some Ostracodes. It might have 
been expected that the shallowest lochs would have had a plankton of 
the pond type, but it has been found that even the smallest lochs 
surveyed had the plankton distinctly lacustrine. A few nearly or quite 
stagnant lochans showed a slight approach to the pond type in the 
presence of Bosmina cornuta and Volvox and in the abundance of 
Rotifers and Algae. 

The remarkable variations of the loch trout, which have so much 
puzzled naturalists cannot be touched on here, but parallel cases are 
found among the smaller animals. Diaptomus gracilis varies remark- 
ably in colour, and is usually constant for each loch, and several other 
Entomostraca vary greatly in size and form; chief among these is 
Daphnia. The typical lacustrine form of this genus, which will be 
referred to as Daphnia lacustris, has an evenly rounded head with a 
depression on the line of the forehead marking off the brow from the 
beak. Where this depression is obliterated the head of the animal has 
a very different appearance, resembling that of a parrot. The form 
differing most from the typical Daphnia lacustris is that in which 
the head is produced upwards into a sort of peak or helmet. For 
convenience, this form will be referred to as Daphnia galeata, though 
it is doubtful if the points of difference are of specific value, and 
intermediate varieties are found. 

After Daphnia, the species which varies most is Bosmina 
obtusirostris. The typical lake-form has a short mucro at the posterior 
angle of the valves. It varies much in size and in colour, being usually 
hyaline, but sometimes purple, or rarely orange and purple. 

During its season Holopedium, from its large size, is very conspicuous 
in those lochs in which it occurs. It is frequently so abundant that it 
chokes up the nets in a short time, and makes it impossible to get a fair 
proportion of the other animals present. It appears in some lochs as 
early as May, and continues till August. 

Commonly a single organism, usually vegetable, will so increase in 
a loch as to form what the Germans call a " Wasserblut." The Algae 
Clathrocystis, Oscillaria, Botryococcus, Anabcena, and Volvox are among 
those which most frequently increase to this extent, but almost any of 
the smaller organisms, as Diatoms, Rotifers, or Protozoa, may on 



THE FRESH- WATER LOCHS OF SCOTLAND. 141 

occasion do so. Asterionella, Xotholca longispina, Asplanchna 
priodonta, Ceratium hiriitidhiella, and even on one occasion the rather 
uncommon Rotifer Dinocharis Collinsii, have been observed to form a 
" Wasserblut " in the shallower lochs. 

The abundance of certain species in a loch on a single visit may be 
exceptional or temporary ; the small lochs may vary greatly at different 
seasons. It is believed that, except for the seasonal appearance of 
certain species which are known to live for only a few months of the 
year, a loch is pretty uniform in character throughout the year. This 
is known to be the case with the large lochs and with some small ones. 

The points to which attention will be called in reviewing the biology 
of the Tay lochs will be the abundance or scarcity of life on the 
whole; the preponderance of one or a few species in each loch; the 
abundance of an animal or plant that is usually scarce; the absence 
or scarcity of some very common species. 

The lochs of the valley of the Earn differ much in size and physical 
conditions, so that they might be expected also to differ much in their 
biology. There is one great lake, Loch Earn, two hill lochs, Turret 
and Uaiue, the latter at a great elevation, one deep but stagnant pond, 
and one shallow artificial dam. 

Loch Earn. The only abundant organism was Diaptomus gracilis, 
which was bright red in colour. There was almost no life at the 
surface, the Diaptomu* being in myriads at a depth of 40 or 50 feet. 
The loch was rather remarkable for the scarcity of common lacustrine 
species. Bythotrephes was somewhat frequent; Polyphemus, Cyclops 
strenuus, and Bosm-ina obtusirostris were present, but not plentiful. 
Daphnia was very rare, only one example being seen. Smaller 
organisms were almost entirely absent, except for a few examples of 
the two commonest pelagic Rotifers : Anurcea cochleare and Xotholca 
longispina, and some unicellular Algae. 

Loch Turret. This was one of the lochs where Holopedium filled 
the net with a slimy mass, and rendered it difficult to catch anything 
else. Diaptomus y radii* , Daphnia (typical D. lacustris), Asterionella, 
Pfridinhun tahulatum were noted. 

Lochan Uaine. This little shallow tarn, in a corrie at a considerable 
elevation, had nothing remarkable in its pelagic life. Diaphanosoma 
brachyuruin was most numerous ; Diaptotnus yradlis, of a brown colour, 
and Polyphemus were common. Only a few examples of Daphnia 
larustrts and Holopedium were seen. 

Loch ^[<>n:ie^clird (or Ochtertyre). This loch, though fairly deep, 
was almost stagnant at the time it was visited. As might be expected 
from this and from the very high surface temperature, life was abundant 
and varied. The collection was green from the abundance of Volvor. 
Bosmina cor nut a, Daphnia lacustris, Diaptomus yracilis (of a brown 



142 BATHYMETRICAL SURVEY OF 

colour), Ceratium hirundinella, Asplanchna, Anurcea cochleare, 
Anabcena were among the most abundant organisms. Many others 
were present in smaller numbers. 

Drummond Pond. This is a shallow and nearly stagnant artificial 
pond, and many species were plentiful in the water. Daphnia 
lacustris was most numerous. Many males and females carrying 
ephippia were present. Other abundant species were Ceriodaphnia 
(some with ephippia), Anurcea cochleare, Conochilus, Asplanchna, 
Notops pygmceus. Volvox was scarce. The beautiful Rhizopod Difflugia 
corona was seen. 

The lochs of Strath Bran, though completely isolated one from 
another, and draining by different streams into the Bran, are fairly 
comparable one with another, being all, with the exception of Loch 
Freuchie, hill lochs of small size, lying at considerable elevations. 

Loch Freuchie. This was one of the lochs where Holopedium for 
the time being abounded to the exclusion of everything else. Only a 
few individuals of Diaptomus gracilis (brown in colour) were seen. 
Hardly any small organisms were noticed. 

Loch Fender. Life was abundant, but few species were present. 
The most numerous animals were Diaptomus (pale brown), Notholca 
longispina, Daphnia (parrot-shaped head), Bosmina longispina, and 
Peridinium tdbulatum. Holopedium was not seen. 

Loch Hoil.- Life was very abundant. The commonest animals were 
Holopedium, Diaptomus gracilis, D. Wierzejskii (blue, red, or red and 
blue), Daphnia, and Asplanchna. 

Loch na Craige. Animals of many species were present, but only 
four were plentiful Diaptomus gracilis (blood-red), Bosmina ob- 
tusirostris (of large size), Daphnia lacustris (very large), and Conochilus 
unicornis. 

Loch Kennard. Some seven or eight species of animals were 
common in the loch, but Diaptomus predominated. D. gracilis and 
D. Wierzejskii were both present. Blood-red individuals of both species 
occurred, and D. Wierzejskii was also seen of the usual blue colour, or 
red and blue. Holopedium, Notholca longispina, and Asplanchna 
priodonta, and the somewhat rare crustacean Latona setifera, were 
numerous. 

Loch Skiach. The characteristic animals were Holopedium, 
Daphnia lacustris (very large), Bosmina obtusirostris (very small, 
purple). Gammarus pulex of large size, and orange colour, was found. 
A few examples of Bosmina were large and brightly coloured, orange 
and purple. 

Loch Tay. Comparing Loch Tay with Loch Rannoch, it is found 
that the plankton differs in several important particulars. Besides the 
common Diaptomus gracilix, there was another species, D. Wierzejtkii , 



THE FRESH- WATER LOCHS OF SCOTLAND. 143 

pretty common in the loch. This is a larger species, usually dark blue 
in colour. It is a northern species, of general occurrence over the 
north and west of Scotland, but hardly known south of Loch Tay. 
Daphnia was always very scarce. Desmids of the genera Staurastrum 
and Arthrodesmus were more numerous than is usual in great lakes. 
As in Loch Rannoch, skeletons of Clathrulina were abundant. 

Lochs lubhair and Dochart. Both these lochs, being very shallow, 
had, at the time they were visited, in addition to the usual pelagic 
species of Diaptomus, Daphnia, and Bosmina, several species in 
abundance which are not truly pelagic. Chydorus sphcericus, Alonopis 
elongata, and Alonella nana were as numerous as the pelagic species. 
Rotifers and Protozoa, especially Rhizopods, were more varied than 
usual. 

Loch Essan. Life was abundant and varied. Daphnia was of three 
forms large typical Daphnia lacustris with rounded head, smaller 
with tall helmet (D. galeata), and an intermediate form. Diaptomus 
gracilis, some dark brown, some hyaline, Polyphemus, Diaphanosoma 
brachyurum, Bosmina obtusirostris, and water-mites (Hydrachnidae), 
which do not usually occur in the open water, were all common. 

Loch Breaclaich. This loch was quite unusual from the great 
numbers of a Rotifer, Asplanchna priodonta, which formed a 
" Wasserblut," appearing as a great slimy mass in the net. 
Diaptomus gracilis (hyaline), Cyclops (dark red), and Diaphanosoma 
brachyurum were seen. 

Loch na Lairige. The characteristic organisms were Bosmina 
obtusirostris (large dark brown, and purple) and a species of Conochilus. 
Daphnia galeata (with tall helmet), Polyarthra, and Diaptomus 
gracilis (pale, immature) were frequent. A few dark red Diaptomus 
gracilis, Sida crystallina, and Bythotrephes were also present. 

Loch Lyon. The biology of this loch was notable for its unusual 
richness. Most abundant were Diaptomus gracilis (pale yellow), 
Bosmina obtusirostris (with somewhat long spine), Cyclops strenuus (of 
large size), and Rotifers of many species. Larvae of Diaptomus were 
exceedingly numerous. 

Lochs Daimh and Giorra. These two lochs are so nearly alike in 
size and so close together, being connected by a river, that they might 
be expected to resemble one another in their biology, but they were 
found to differ greatly. In Loch Daimh, Holopedium was abundant, 
but very young. Diaptomus gracilis (hyaline, with dark brown eggs) 
was numerous, and the larvae still more so. Nothing else was found in 
any numbers. Loch Giorra, on the other hand, had half a dozen 
common species Diaptomus gracilis (pale yellow), Cyclops strenuus, 
Daphnia lacustris, Bosmina obtusirostris, Dinobryon, and Tabellaria 
(two species). Holopedium was not seen. 



144 BATHYMETRICAL SURVEY OF 

Loch Derculich. The characteristic animals were Diaptomus 
(brown), Daphnia lacustris (with parrot-shaped head), Bosmina ob- 
tusirostris (with long beak), Notholca longispina, and Dinobryon. 

Loch Scoly. The most abundant animals were Daphnia lacustris, 
Diaptomus gracilis (dark brown, mostly immature), Conochilus volvox, 
Bosmina obtusirostris (small), and Peridinium tabulatum. 

Loch Rannoch. The plankton of Loch Rannoch may be fairly 
taken as" the type of all the large Scottish lochs. Almost every one of 
the species included in the list of the lacustrine organisms was found in 
it, and there was nothing in it not given in the list. Of the Entomos- 
traca, Bosmina was the most abundant. Skeletons of the Rhizopod 
Clathrulina elegans, though this is not a pelagic animal, were always 
found in it. The biology of the littoral region of the loch has 
been studied with some care by Mr. D. J. Scourfield and others, 
but as this region has not been studied in the other lochs of the 
system, it is thought better not to enter into the details of it 
here. 

Loch Ba. Most of the common pelagic animals were not seen, while 
many species belonging rather to the shore (or littoral) fauna were 
numerous, as Eurycercus lamellatus, Acroperus harpce, Alonella nana 
and A. excisa, Alona affinis and A. guttata, and Chydorus sphccricus. 
Many Rhizopods were observed, as well as mites and Ostracodes. 

Loch Laidon. Only the Entomostraca of this loch were studied 
by Mr. D. J. Scourfield. The species were all the same as in 
Loch Rannoch. No collections were made of the other groups of 
animals. 

Lochan Sron Smeur. Notwithstanding the high elevation and the 
early season at which it was examined, this loch was found to be 
exceptionally rich in both animals and plants, particularly in Rotifers, 
Rhizopods, and Desmids. Holopedium was here seen unusually early 
in the season. Besides the ordinary pelagic animals, Diaptomus, 
Daphnia, Bosmina, &c., Latona setifera was present. 

Loch Bhac. The commonest animals were Diaptomus gracilis (red), 
Bosmina obtusirostris (with long beak), Daphnia lacustris, Diaphano- 
soma brachyurum. Among the Rotifers was the brilliant red and blue 
Notops pygmceus, and the curious Desmid Micrasterias Wallichii was 
present. 

Loch Con. Entomostraca were few, and Algae more numerous 
than usual. The commonest animal was Bosmina obtusirostris (small). 
Diaptomus gracilis (some large, yellow, others red). The Rotifer 
Notops pygmceus was unusually large. 

Loch Tilt. In common with a few other lochs, usually lying at 
considerable elevations, the only common animal was Diaptomus 
gracilis, so bright red in colour that the net, when taken up, seemed 
filled with blood. Hardly anything else was seen. 



THE FRESH- WATER LOCHS OF SCOTLAND. 145 

Loch Moraig. Entomostraca were here scarce, and Protozoa and 

Algae abundant. The commonest organism was a form of Ceratium 

'tdinella, which was so abundant as to constitute a " Wasserblut." 

Loch Broom. This shallow, marshy pool, with Menyanthes growing 
almost everywhere, yet had a quite ordinary lacustrine fauna, including 
Diaptomus (dark brown), Daphnia lacustris (very large), Cyclops 
strenuus (large hyaline), Bythotrephes . Conochilus was much the 
commonest animal. An unusual form of Ceratium hirundinella, 
having both the median spines long, occurred. 

Loch Or die. The most abundant animals at the time this loch was 
visited wereHolopedium, Daphnia (parrot-shaped head), and Diaptomus 
(hyaline). Bosmina of two forms was found B. obtusirostris (small) 
and B. longispina. 

Loch nan Eun. The highest loch in the Tay system visited. The 
predominant animal was Diaptomus yracilis (blood-red); Daphnia 
hu-u.it r is (very large), Bosmina obtusirostris, and several species of 
Desmids, notably Staurastrum arctiscon, were present in some numbers. 
There was a scarcity of smaller organisms. 

Loch Shechernich. The water was turbid from the abundance of 
life. The most conspicuous examples were Diaptomus (dark red, red 
and yellow, red and blue, or all blue), probably D. Wierzejskii, 
Daphnia (parrot-shaped head), Bosmina (very large, purple), Xotholca 
longispina, and Polyarthra. Asterionella was of a smaller size than 
usual. Numbers of a small yellow water-mite were seen. 

Loch Auchenchapel. Ceratium hirundinella formed a " Wasser- 
blut " in the loch at the .time it was visited. Other common animals 
were Bosmina obtu*iro*tris, Daphnia lacustri-s (small), Diaptomus 
(reddish), f'onocliilus. 

Loch of Lintrathen. The water was very clear, and organisms 
sparingly distributed. Daphnia lacustris (large) and Diaptomus 
y rat: Hi* (hyaline) were the only animals at all common. 

Lnrh BtnachaUy. Hnlopedium was common on the surface, but not 
below. Diaptomus t/racilis (brown, mostly immature) and Daphnia 
(large) were most abundant. Bosmina was scarce. 

Long Loch. Very few animals were present, the commonest being 
f(irtt*tris, Diaptomus yracilis (hyaline), and Conochilus. 

Pitlyal Lorji. This differed from most lochs visited about the same 
time in the general scarcity of life, especially of Entomostraca. It was 
one of the few lochs in the system where Bosmina cornuta took the place 
of the common B. obtusir<>*fri. There was a " Wasserblut " of a pale 
filamentous Alga. Volvo/: and several other Algae occurred. Although 
in those various respects the biology approached the pond type, 
Leptodora was rather numerous. 

For far Loch. The water was very turbid throughout, yet the fauna 
was mainly lacustrine, the commonest animal being Cyclops strenuus. 

L 



146 BATHYMETRICAL SURVEY OF 

Daphnia lacustris (large) was also common. The Cyclops was covered 
with parasites of many species, both animal and vegetable. 

The lochs which are drained by the Lunan burn form a connected 
series, all of moderate size or very small and shallow, several being 
quite stagnant and overgrown with weeds. The most important are 
Lochs of the Lowes, Drumellie, and Clunie, the last being the deepest 
of the whole chain. Volvox was present in most of the lochs. 

Loch of Craiglush. Most of the ordinary pelagic animals were seen. 
Holopedium was abundant. Daphnia was tinged with pink, and some 
males were seen; Diaptomus was dull brown; Bosmina was small. 
Several small Algae, as Volvox, Pediastrum, Eudorina, were common, 
and several Rotifers, as Sacculus viridis and a species of Synchceta. 

Loch of the Lowes. The plankton resembled that of Loch Craiglush, 
but differed in a few points. Holopedium was more numerous, Daphnia 
larger and not pink, Bythotrephes was seen, and there were fewer Algae 
and Rotifers. 

Loch of Butterstone. Life was abundant, and the species were 
almost all the same as in Loch Craiglush. There was less difference 
between those two lochs than between Loch Craiglush and Loch of the 
Lowes, which are connected by a broad canal. The Daphnia was 
pink-tinged as in Loch Craiglush, and there were some males. Another 
form of Daphnia also occurred, larger, and with a purple spot on each 
valve. 

Lochs Drumellie and Clunie. These two lochs may be treated 
together, as they are connected by a short burn and differ little in the 
character of the plankton. The Daphnia in both had the parrot-shaped 
head which results from the elimination of the depression in the fore- 
head. Bosmina was not noted in either. Volvox was more plentiful in 
Loch Drumellie, and Leptodora was common in it and not seen in 
Loch Clunie. 

Rae Loch (or Ardblair Loch). The most common animal was 
Notholca longispina. The Daphnia was small, the Diaptomus mostly 
immature, and Bosmina was not seen. A large bizarre-shaped In- 
fusorian with green body-contents was numerous. 

Black Loch. The only common organisms were Diaptomus (pale 
red), Daphnia (large), Polyphemus, and some small Diatoms. 

White Loch and Fingask Loch. These two lochs, which are con- 
nected by a short burn, are very similar, Daphnia (large) being much 
the most abundant animal, a few bearing ephippia and some males 
being seen. Diaptomus was hyaline and immature. Volvox was more 
plentiful in Fingask Loch. Lejjtodura was only seen in the White 
Loch. 

Stormont Loch. The water of this stagnant pond was quite turbid 
and yellow in colour from the superabundance of Daphnia. The nets 
could not be drawn through the water in the usual way without getting 



THE FRESH- WATER LOCHS OF SCOTLAND. 147 

quite choked with animals. A single dip of the net, by which about 
half a gallon of water would be strained, collected enough material to 
fill a 2-oz. bottle. The Daphnia was of two forms, one small and the 
other much larger than usual, and 'many males were seen. There was 
little else in the loch, only Diaptomus (hyaline) and a species of 
Aiiabcena being at all plentiful. 

Monk Myre. Notholca longispina formed a " Wasserblut " here, 
giving the collection a reddish colour. Diaptomus (grey or hyaline), 
Bosmina cornuta, and Polyphemus were common. 



148 



BATHYMETRICAL SURVEY OF 



LOCHS OF THE INVER BASIN. 

SEVEN lochs which drain into Loch Inver were sounded by the Lake 
Survey, viz. : Lochs Assynt, Leitir Easaich, Awe, Maol a' Choire, 
Beannach, Druim Suardalain, and na Doire Daraich; the largest and 




Eng. Miles 



FIG. 27. INDEX MAP OF THE INVER, ROE, KIRKAIG, POLLY, AND GARVIE BASINS 



most important is Loch Assynt (see Index Map, Fig. 27). There were a 
few small lochs belonging to this drainage basin which were not 
sounded, because there were no boats on them at the time the Lake 
Survey staff visited the district. 

Loch Assynt (see Plate XXXV.). Loch Assynt lies about four miles 
to the E.N.E. of Loch Inver, and the road from Lairg to Lochinver 






THE FRESH- WATER LOCHS OF SCOTLAND. 149 

passes along its northern shore. It receives the outflow from Lochs 
Awe, Maol a' Choire, and Leitir Easaich, and its waters are discharged 
by the river Inver, which, after a wild and tortuous course of over five 
miles, falls into Loch Inver. It is a good fishing loch, containing trout, 
sea-trout, salmon, and Salmo ferox. The ground around the western 
end is low, but on proceeding eastwards it becomes higher, Beinn 
Gharbh rising on the south shore to over 1700 feet, while on the north 
shore Quinag attains 2600 feet, Ghlas Bheinn 2500 feet, Beinn Uidhe 
2300 feet, and farther to the south-east Coniveall and Ben More Assynt 
reach 3200 feet. On a promontory on the north shore about a mile 
from Inchnadamph stand the ruins of Ardvreck Castle, once a strong- 
hold of the M'Leods and afterwards of the Mackenzies. There are a 
few small islands and islets near the shore in the western half of the 
loch. 

Loch Assynt has the reputation of being very wild and rough, and it 
certainly fully maintained that reputation during the week spent upon 
it by the staff of the Lake Survey. The general trend of the loch is 
west-north-west and east-south-east, while the western end bends 
sharply at Loch Assynt lodge to the south-west, and the eastern end 
bends less sharply to the south-east. It is 6J miles in length, and 
nearly a mile in maximum breadth, the mean breadth being half a 
mile, or 8 per cent, of the length. Its waters cover an area of nearly 
2000 acres, or over 3 square miles, and it drains an area fourteen times 
greater, or over 43 square miles. Nearly 400 soundings were taken, 
the maximum depth observed being 282 feet. The volume of water 
contained in the loch is estimated at 8,730,905,000 cubic feet, and the 
mean depth at 101 feet, or 36 per cent, of the maximum depth. The 
length of the loch is 120 times the maximum depth and 330 times 
the mean depth. 

The floor of Loch Assynt is rather irregular, as shown by the 
longitudinal section and two cross sections on the map; this is more 
especially the case in the half lying to the north of the medial line. 
The 100-feet contour running along the northern shore is of a most 
sinuous character, quite independent of the shore-line, and is in striking 
contrast to the same contour running along the southern shore. In the 
position of the cross section E F, moreover, the 150-feet and 200-feet 
contours show a curious prolongation in a northerly direction, and 
here an isolated sounding of 210 feet was recorded separated from the 
200-feet area by a sounding of 198 feet. The 50-feet, 100-feet, and 
150-feet basins are continuous areas, while the area over 200 feet in 
depth is cut up into four portions, and that over 250 feet in depth into 
three portions. The 50-feet basin extends practically from one end of 
the loch to the other ; the 100-feet basin stretches from 200 yards from 
the eastern end to beyond Rudh' an Alt-toir, where the loch bends 
sharply to the south-west, and is 5 miles in length ; the 150-feet basin 



150 BATHYMETRICAL SURVEY OF 

extends from about a quarter of a mile from the east end to Rudh' an 
Alt-toir, and is 4f miles in length. The four areas exceeding 200 feet 
in depth, proceeding from east to west, are (1) a large eastern basin 
1J miles in length, extending from south-east of Ardvreck Castle to 
north of Garbh Dhoire ; (2) a small basin lying 150 yards to the west 
of the first-mentioned, based on a sounding of 210 feet; (3) a large 
western basin 1| miles in length, extending from south of the eastern 
islands off the north shore to north of Torr a' Chail; and (4) a small 
basin less than 100 yards further west, based on a sounding of 214 feet. 
The three 250-feet basins are all very narrow, one enclosed in the large 
eastern 200-feet basin, |-mile in length and with a maximum depth of 
264 feet, the other two enclosed in the large western 200-feet basin, the 
smaller having a maximum depth of 270 feet, the larger being nearly a 
mile in length and including the maximum depth of the loch (282 feet), 
which occurs to the north of Eilean Assynt. It will be observed that 
the deep channel does not coincide with the central axis of the loch, but 
lies for the greater part of its course much nearer the southern than the 
northern shore ; opposite Ardvreck Castle, however, it crosses over and 
lies nearer the northern shore in the eastern end of the loch. The 
numerous large bays along both shores were found to be fairly deep. 

The areas of the lake-floor at different depths, and the percentages 
to the total area of the loch, are as follows : 

to 50 feet, 572 acres 29 per cent. 

50 ,, 100 559 28 

100,, 150 351 18 

150,, 200 270 14 

200,, 250 184 9 

Over 250 , 46 , 2 



1982 , 100 



More than half the entire lake-floor is covered by less than 100 feet 
of water, and the areas on both sides of the 50-feet contour-line are 
nearly equal, indicating a moderate and uniform average slope down 
to the depth of 100 feet, beyond which depth the slope becomes much 
steeper. 

Loch Assynt was surveyed on September 12 to 18, 1902. On the 
12th the elevation of the lake-surface above the sea was determined, 
by levelling from bench-mark, as being 215*1 feet; subsequently heavy 
rains set in, so that on the 16th the water had risen to the extent of a 
foot, and on the 18th to the extent of 16 inches, above the level on the 
12th, and the later soundings were corrected in order to bring them 
into agreement with the earlier ones. When levelled by the officers of 
the Ordnance Survey on September 9, 1871, the surface of the water 



THE FRESH-WATER LOCHS OF SCOTLAND. 151 

was found to be 214-8 feet above sea-level. The highest drift-mark 
observed was 4J feet above the level of the loch on September 12, 1902. 
Temperature Observations. Temperature observations taken in 
Loch Assynt showed very little variation in the temperature of the 
surface water during the week occupied by the survey, the highest 
reading recorded being 55'0 F. at 10 a.m. on September 12, towards 
the east end of the loch, and the lowest 53-6 at 10 a.m. on the 16th, 
also near the east end. Beneath the surface the fall of temperature 
was also small, as shown by the following serial observations taken at 
noon on September 16, to the north of Garbh Dhoire : 

Surface 53 "7 Fahr. 

50 feet ... 53-5 

150 .. 52-7 

240 52-0 

The range of temperature from surface to bottom was thus only 1 0> 7, 
and the extreme range observed throughout the whole body of water 
was only 3'0. 

Loch Leitir Easaich (see Plate XXXV.). Loch Leitir Easaich (or 
Letteressie) lies immediately to the west of, and at a slightly higher 
level than, Loch Assynt, into which it flows by a stream only a few 
yards in length. The ground around it is low. The waterfall at its 
western end, from which the loch derives its name, is very fine. Loch 
Leitir Easaich is considerably over half a mile (or about 1100 yards) in 
length, the maximum breadth being two-fifths of a mile (or about 700 
yards), and the mean breadth about one-eighth of a mile (or about 230 
yards), or 21 per cent, of the length. Its waters cover an area of about 
62 acres, and it drains an area thirty-three times greater, or 2| square 
miles. Nearly 30 soundings were taken, the maximum depth observed 
being 70 feet. The volume of water is estimated at 44,909,000 cubic 
feet, and the mean depth at 20 feet, or 28 J per cent, of the maximum 
depth. The loch is extremely irregular in outline, the main body 
trending north and south, with an arm running in an easterly direction 
towards Loch Assynt. The maximum depth observed in this arm was 
31 feet, separated by shallower water from the deep basin in the main 
body of the loch, where there is a small area exceeding 50 feet in depth 
towards the western shore. The areas between the contour-lines, and 
the percentages to the total area of the loch, are as follows : 

to 25 feet 36 acres 68 '8 per cent. 

25 50 22 23-6 

Over 50 , 4 7'6 



62 , 100-0 



152 BATHYMETRICAL SURVEY OF 

Over two-thirds of the entire area of the loch is thus covered by less than 
25 feet of water. Loch Leitir Easaich was surveyed on September 18, 
1902, the elevation of the water surface being 217 feet above the level 
of the sea, and half a foot higher than the water in Loch Assynt on the 
same date. After very heavy rains the two lochs must stand at the same 
level. The boatmen stated that the water in Loch Leitir Easaich would 
rise very little higher than on the date surveyed, and would fall about 
two feet lower than this level. 

Loch Maol a' Choire (see Plate XXXVI.). Loch Maol a' Choire 
(or Mulach-Corrie, or the Gillaroo Loch) is situated about two miles to 
the south-west of Inchnadamph, and flows by the Allt na Glaice Motre 
into the river Traligill, which falls into the head of Loch Assynt near 
the entrance of the river Loanan. The loch derives one of its names 
from the supposed resemblance of its fish to the Gillaroo trout of Lough 
Melvin; in shape the trout are very deep and thick, and hence very 
heavy in proportion to their length. Loch Maol a' Choire trends in a 
north and south direction, and is about 600 yards in length by about 
250 yards in maximum breadth. It covers an area of about 20 acres, 
and drains an area of about 512 acres an area twenty-five times greater 
than that of the loch. Forty soundings were taken, the maximum depth 
observed being 8 feet. The volume of water is estimated at 4,452,000 
cubic feet, and the mean depth at 5 feet. The loch is fairly uniform 
in depth, deepening gradually on proceeding from the southern end 
towards the north-western shore, off which two soundings of 8 feet were 
taken. It was surveyed on September 13, 1902 ; its elevation above the 
sea was not determined by levelling, but is between 800 and 900 feet, 
the ground surrounding it being covered by peat. The temperature of 
the water was uniform at 49-2 on the date of the survey. 

Loch Awe (see Plate XXXVI.). Loch Awe is situated nearly four 
miles to the south of Inchnadamph, by the side of the road leading to 
Alltnacealgach. The ground to the south-east is peat-covered, while 
Canisp rises on the south-west, Cnoc an Leathaid Bhuidhe on the west, 
and Beinn an Fhuarain on the east. Its principal feeder, the burn flow- 
ing from Loch na Cruagaich, enters the loch at its northern end, within 
30 yards of the mouth of the river Loanan, which carries the outflow 
into Loch Assynt. The fishing has been much improved of late years, and 
it is now a good salmon loch, the fish running through Loch Assynt into 
it. Loch Awe trends north and south, and is over four-fifths of a mile 
(or about 1400 yards) in length, with a maximum breadth of less than 
one-third of a mile (or about 530 yards), the mean breadth being about 
one-half of tbis. It covers an area of about 86 acres, and drains an area 
twenty-four times greater, or 31 square miles. Over 60 soundings were 



THE FRK>H-\VATKK LOCHS OF SCOTLAND. 153 

taken, the maximum depth observed being 7 feet. The volume of water 
is estimated at 17,751,000 cubic feet, and the mean depth at nearly 
5 feet. Loch Awe is thus very shallow, a large part being overgrown 
by weeds and rushes; the maximum depth of 7 feet was observed in 
two places in the northern portion of the loch. It was surveyed on 
September 23, 1902. The elevation above the sea was determined, by 
levelling from bench-mark, as being 504 feet. This is almost identical 
with the level observed by the officers of the Ordnance Survey on 
September 6, 1871, viz., 504-1 feet. The temperature of the water was 
found to be uniform at 53'5. 

Loch Beunnach (see Plate XXXVI.). Loch Beannach lies about 
two miles to the west of Loch Assynt and four miles from Lochinver. 
It flows into Loch Bad nan Aighean (which was not sounded), thence 
by a short stream into the river Inver after leaving Loch Assynt. It 
is most irregular in outline and in conformation, with numerous islands, 
the majority of which are thickly wooded and give to the loch a beautiful 
appearance. Loch Beannach is 1J miles in length, with a maximum 
breadth of less than one- third of a mile (or about 530 yards), the mean 
breadth being about one-seventh of a mile (or about 250 yards). Its 
waters cover an area of about 117 acres, and it drains an area ten 
times greater, or nearly two square miles. Over 60 soundings were 
taken, the maximum depth observed being 38 feet. The volume of 
water is estimated at 67,348,000 cubic feet, and the mean depth at 13 
feet. As already indicated, the floor of the loch is very uneven. It falls 
in four places below the 20-feet level, the deepest part of the loch being 
in the south-western portion, where three soundings exceeding 30 feet 
were taken, the maximum depth of 38 feet having been observed about 
100 feet to the north of the small island lying off the southern shore, 
indicating in this position a slope of 1 in 2'6. The area of the lake-floor 
covered by less than 25 feet of water is about 105 acres, or 89 per cent, 
of the total area of the loch. Loch Beannach was surveyed on Septem- 
ber 19, 1902. Its elevation above the sea could not be determined, but 
must be between 230 and 280 feet. The highest drift-mark observed 
was 3 feet above the level of the water on the date of the survey, and 
the boatman stated that the water might fall about 2 feet lower ; thus 
a range in the level is indicated of about 5 feet. The temperature of the 
surface water was 52-5, and at a depth of 30 feet 52-0. The range 
of temperature throughout the body of water was thus very small. 

Loch Druim Suardalain (see Plate XXXVI.). Loch Druim 
Suardalain lies about a mile to the east of Loch Inver and half a mile 
to the east of Loch na Doire Daraich, into which it flows by the Uidh 
a' Bhalgain. Its principal feeder is the Amhainn Bad na h-Achlaise, 



154 BATHYMETRICAL SURVEY OF 

bearing the outflow from Loch na Gainimh in the Canisp forest. The 
ground around the loch is low. It is three-quarters of a mile in length, 
and a quarter of a mile in maximum breadth, the mean breadth being 
one-sixth of a mile. Its waters cover an area of about 79 acres, and it 
drains an area 105 times greater an area of nearly 13 square miles. 
Seventy-five soundings were taken, the maximum depth observed being 
31 feet. The volume of water is estimated at 35,408,000 cubic feet, and 
the mean depth at over 10 feet. Loch Druim Suardalain is irregular in 
outline, with a few islands, and the conformation of the bottom is 
peculiar. Towards the eastern end is a small area exceeding 20 feet in 
depth, the deepest sounding in this position being 29 feet, but the 
maximum depth of the loch (31 feet) was observed quite close to 
the south-western shore, apparently a deep hole surrounded by much 
shallower water. The area of the lake-floor covered by less than 10 
feet of water is about 45 acres, or 58 per cent, of the total area of the 
loch. The loch was surveyed on September 15, 1902, and the elevation 
above the sea was determined, by levelling from bench-mark, as being 
134-5 feet; when levelled by the officers of the Ordnance Survey on 
September 19, 1871, the elevation was found to be 133-1 feet above sea- 
level. The temperature of the water was found to be uniform at 53 0> 2. 

Loch na Doire Daraich (see Plate XXXVI.). Loch na Doire 
Daraich (or Loch Culag, as it is more generally called in the district) 
is situated about a quarter of a mile to the south-east of Loch Inver, 
into which it flows by the Amhainn na Culeig ; its chief supply of water 
is derived from Loch Druim Suardalain. The surrounding ground is 
low, but is steeper to the south and south-west, and on the western side 
thickly wooded. It is very irregular in outline and conformation, and 
the two arms projecting southwards are to a large extent filled with 
weeds. The length from south-west to north-east is half a mile, and the 
maximum breadth a quarter of a mile, the mean breadth being one- 
seventh of a mile. Its waters cover an area of about 44 acres, and it 
drains directly an area exceeding a square mile, but since it receives the 
outflow from Loch Druim Suardalain, its total drainage area is about 
14 square miles, an area 203 times greater than that of the loch. Over 
40 soundings were taken, the maximum depth observed being 9 feet. 
The volume of water is estimated at 6,922,000 cubic feet, and the mean 
depth at 3 J feet. The loch is very shallow, but it is curious to note that 
the deeper soundings were taken near shore ; soundings of 5 and 6 feet 
were recorded in four places close to the shore, an isolated sounding of 
7 feet was taken at the entrance of the inflowing burn from Loch Druim 
Suardalain, while the maximum depth of the loch was observed close to 
the large promontory on the western shore. Loch na Doire Daraich 
was surveyed on September 20, 1902, the elevation of the lake-surface 
being 72*5 feet above the sea; when levelled by the officers of the 



THE FRESH- WATER LOCHS OF SCOTLAND. 155 

Ordnance Survey on August 26, 1870, the elevation was found to be 
73 '7 feet above sea-level. The boatman stated that the water may rise 
2 feet above its level on September 20, 1902, and fall 3 feet lower, 
giving a range of 5 feet. Temperature observations gave 50'5 at the 
surface, and 50'l at a depth of 7 feet. 



156 BATHYMETRICAL SURVEY OF 



LOCHS OF THE ROE BASIN. 

THE two principal lochs only in this basin, Lochs Crocach and an Tuirc, 
were surveyed; the smaller ones could not be sounded from lack of 
boats. 

Loch Orocach (see Plate XXXVII.). Loch Crocach lies about three 
miles to the north of Loch Inver, and about a mile to the north-west of 
Loch an Tuirc, into which its waters are discharged. It is most 
irregular in outline and in conformation, and is studded with islands 
large and small; indeed the insulosity (i.e., the ratio between the area 
of the islands and the total area of the loch) is one of its distinguishing 
characteristics, being probably higher than in any other loch visited by 
the Lake Survey, the lochs most nearly approaching it in this respect 
being Lochs Maree and Lomond. The islands are mostly congregated 
in the large western bay; they are low, heather-covered, and not 
wooded as in the majority of the lochs in the district. The ground 
around the loch is low; from 350 to 700 feet above the sea. Loch 
Crocach trends north-east and south-west, and is nearly 1| miles in 
length and over one-third of a mile (or about 700 yards) in maximum 
breadth, the mean breadth being about one-sixth of a mile (or rather 
less than half the maximum breadth). Its waters cover an area of 
about 160 acres (or one-quarter of a square mile), exclusive of the 
numerous islands, and it drains an area seven times greater, or If square 
miles. Nearly 80 soundings were taken, the maximum depth observed 
being 71 feet. The volume of water is estimated at 147,987,000 cubic 
feet, and the mean depth at nearly 17 feet. Loch Crocach is deeper 
than the other small lochs in this district. A large 2 5 -feet area occupies 
the greater portion of the length of the loch to the north-west of the 
islands ; a second smaller area occurs in the south-western expansion of 
the loch, and a third very small area lies near the south-western end 
of the loch, based on a sounding of 30 feet. The bottom falls in two 
places below the 50-feet level, the larger basin being centrally placed, 
between the entrance of the Uidh nan Lion and the largest of the 
islands, with a maximum depth of 64 feet, the smaller but deeper basin 
lying in the south-western expansion of the loch, the maximum depth 
of 71 feet having been observed quite close to the small island off the 



THE FRESH- WATER LOCHS OF SCOTLAND. 157 

southern shore. The areas between the consecutive contour-lines, and 
the percentages to the total area of the loch, are as follows : 

to 25 feet 109 acres 68 '3 per cent. 

25 50 45 28-0 

Over 50 , 6 . 3'7 



160 , 100-0 



Loch Crocach was surveyed on September 17, 1902, but the elevation 
of the lake-surface above the sea could not be determined ; the elevation 
must be between 350 and 370 feet above sea-level. The boatman stated 
that the water might rise 2 feet above, and fall 3 feet below, the level 
on the date of the survey. 

Temperature Observations. Temperature observations showed a 
greater variation than was observed in the larger and deeper Loch 
Assynt, as will be seen from the following serial taken at 2.30 p.m. on 
September 17, 1902: 

Surface 537 Fahr 

40 feet 53 2 

70 ;, 50-8 ,, 

This series shows a range of 3, the greatest fall of temperature 
occurring in deep water below 40 feet. 

Loch an Tuirc (see Plate XXXVII.). Loch an Tuirc is situated 
about two miles north-east of Loch Inver, and over a mile to the west 
of Loch Beannach. It receives the outflow from Loch Crocach, and 
flows by the Uidh nan Caorach into Loch an Aite Mhoir, thence 
through three other small lochs into Loch Roe. The ground around the 
loch is low, the greatest elevation being one of 400 feet to the north-west 
of the loch. Islands are not so numerous in this loch as in the neigh- 
bouring Lochs Beannach and Crocach; weeds are very abundant in 
some parts of the loch. Loch an Tuirc trends north-east and south- 
west, and is irregular in outline and conformation. There is a con- 
striction near the centre of the loch, which cuts the deeper water into 
two portions, and the loch narrows gradually towards the outflow at the 
south-west end. It is about four-fifths of a mile (or about 1400 yards) 
in length, with a maximum breadth of one-fifth of a mile (or over 300 
yards), the mean breadth being one-tenth of a mile. Its waters cover 
an area of about 53 acres, and it drains directly an area of about 1J 
square miles, but, since it receives the outflow from Loch Crocach, its 
total drainage area is nearly 3 square miles. Nearly 100 soundings 
were taken, the maximum depth observed being 39 feet. The volume of 
water is estimated at about 24,787,000 cubic feet, and the mean depth 
at 10 \ feet. The portion of the loch to the north-east of the central 



158 BATHYMETRICAL SURVEY OF 

constriction is shallow and obstructed by weeds ; a small area exceeding 
10 feet in depth runs along the southern shore, the maximum depth 
therein being 13 feet. The wide portion of the loch to the south-west of 
the constriction forms a regular deep basin, the maximum depth of 39 
feet being found in the north-eastern part of the basin. The areas at 
different depths, and the percentages to the total area of the loch, are 
as follows : 

to 10 feet 35 acres 65 '8 per cent. 

10 25 12 23-2 

Over 25 , 6 , 11 -0 



53 , 100-0 



Loch an Tuirc was surveyed on September 17, 1902, but the elevation 
of the lake-surface above the sea could not be determined ; the elevation 
is apparently slightly under 200 feet. Temperature observations at 
3 p.m. gave identical readings of 53'0 at the surface and at depths of 
20 and 30 feet. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



159 



LOCHS OF THE KIRKAIG BASIN. 

THE lochs belonging to this basin form a connected series : Loch 
Borralan flows by the Ledmore river into the Ledbeg river, which 
farther on joins the Na Luirgean, bearing the outflow from Loch 




FIG. 28. LOCH BORRALAN, FROM THE HOTEL ; CUL MOR IN THE DISTANCE. 

(Photograph by H. Anderson.) 



Urigill, and together they flow into the Cam Loch, which empties itself 
into Loch Veyatie, thence into Loch Fionu, and thence by the Kirkaig 
river into Loch Kirkaig. Lochs Veyatie, Fionn, and Borralan lie 
partly in Ross-shire and partly in Sutherlandshire, the boundary 
running down the centre of the two first-named lochs, and across the 
south-eastern end of Loch Borralan. All the lochs are good trout lochs, 
and Loch Veyatie contains also Salmo feroz, while char are numerous 
in Loch Borralan. 



160 BATHYMETRICAL SURVEY OF 

Loch Borralan (see Plate XXXVI.). Loch Borralan (or Borrolan 
or Boarlan) trends north-west and south-east, and the road from Lairg 
to Inchnadamph runs along its north-eastern shore; Aultnacallagach 
Inn is situated on the road close to the loch near its south-eastern end. 
The ground around the loch is low except to the north, where Cnoc na 
Sroine rises to 1300 feet; to the south-west the ground is thickly 
covered with peat. The abundance of char in the loch is remarkable 
considering its shallowness. Weeds were seen growing on the bottom 
almost everywhere, and over large areas they reach to the surface. It is 
over a mile in length, with a maximum breadth of nearly a quarter of a 
mile (or about 400 yards), the mean breadth being about one-sixth of a 
mile (or over 300 yards). Its waters cover an area of about 118 acres, 
and it drains an area 34 times greater, or 6J square miles. Over 60 
soundings were taken, the maximum depth observed being 21 feet. 
The volume of water is estimated at 49,324,000 cubic feet, and the mean 
depth at 9J feet. The maximum depth of 21 feet was observed towards 
the south-eastern end, opposite the entrance of the Allt nan Cealgach ; 
in the north-western portion of the loch a maximum depth of 16 feet 
was found, the 10-feet contour-line being continuous almost from end to 
end of the loch. Loch Borralan was surveyed on September 1, 1902. 
The elevation of the lake-surface above the sea was determined, by 
levelling from bench-mark, as being 459-7 feet, which is almost identical 
with that observed by the Ordnance Survey officers on August 31, 1871, 
viz., 459-8 feet. According to the boatman, the water in the loch might 
fall about 4 inches lower than on the date of the survey, and in 
exceptional floods might rise 5 feet higher. Temperature cbservations 
at 3 p.m. gave identical readings of 56-7 at the surface and at a depth 
of 16 feet. 

Loch Urigill (see Plate XXXVI.). Loch Urigill (or Urigall) lies 
less than a mile to the south-west of Loch Borralan. The ground 
around the loch is low and covered with peat. Like Loch Borralan, 
it trends in a north-west and south-east direction; in fact, nearly all 
the lochs in this district generally trend north-west and south-east, as 
will be seen from the small index map (Fig. 27). It is nearly two miles 
in length, with a maximum breadth of nearly three-quarters of a mile, 
the mean breadth being nearly half a mile. Its waters cover an area 
of about 500 acres (or over three-quarters of a square mile), and it drains 
an area 14 times greater, or 11 square miles. Nearly 130 soundings 
were taken, the maximum depth observed being 40 feet. The volume of 
water is estimated at 285,088,000 cubic feet, and the mean depth at 
13 feet. Loch Urigill is, on the whole, very shallow, nearly 99 per cent, 
of the lake-floor being covered by less than 25 feet of water, and weeds 
are abundant in some places. The 10-feet area is continuous from close 
to the north-west end to near the south-east end, opposite the entrance 



THE FRESH-WATER LOCHS OF SCOTLAND. 



161 



of the Allt nam Meur. Midway along the loch, towards the north- 
eastern shore, is a rise of the bottom covered by only 3 feet of water. 
The deepest part of the loch is near the north-west end, where there is 
a small central area exceeding 20 feet in depth, the maximum depth 
being 40 feet ; this little depression is well denned by a steep gradient. 
Loch Urigill was surveyed on August 30, 1902. The level of the loch 
could not be determined ; when visited by the officers of the Ordnance 
Survey on October 5, 1871, the elevation was found to be 514-7 feet 
above the sea. 




f- -W:^*^ 




FIG. 29. LOCH TJRIGILL, WITH SUILVEN AND CANISP IN THE DISTANCE. 

(Photograph by Mr. H. Anderson.) 



Temperature Observations. Temperature observations taken at 
4 p.m. on August 30, 1902, gave the following results: 



Surface 
10 feet 
20 ., 
3o . 



57 -2 Fahr. 
56-0 ,, 
56-0 

55 -8 



Cam Loch (see Plate XXXVIII.). Cam Loch (or Loch Cama) lies 
about a mile to the north-west of Loch Urigill, and a mile to the west 
of Ledmore. It is extremely irregular in outline and in conformation, 
and includes one large and several small islands. The principal feeder 
is the stream bearing the outflow from Lochs Borralan and Urigill, 
which enters the loch at its south-eastern end, and here also is the exit 
of the loch, the Amhuinn Mhor after a course of a few hundred yards 



162 



BATHYMETRICAL SURVEY OF 



falling in a magnificent cascade into Loch Veyatie. The ground in the 
immediate vicinity of the loch is low, but to the east lies Cnoc na Sroine, 
and to the north-east Cnoc na Leathaid Bhuidhe, while to the west- 
north-west Suilven, and to the north Canisp, form remarkably fine 
objects, which catch the eye from every part of the loch. The length of 
the loch is 2 1 miles, the maximum breadth over three-quarters of a 
mile, and the mean breadth over one-third of a mile. Its waters cover 
an area of about 647 acres, or over one square mile, and it drains 
directly an area of over 16 square miles, but since it receives the 
outflow from Lochs Borralan and Urigill its total drainage area is about 




FIG. 30. CAM LOCH, WITH SUILVEN IN THE DISTANCE. 

h bi/ Rev. H. N. Jion/ir. i 



33J square miles. Over 200 soundings were taken, the maximum 
depth observed being 122 feet. The volume of water is estimated at 
1,062,543,000 cubic feet, and the mean depth at nearly 38 feet. The 
south-eastern portion of the loch is shallow, very few soundings ex- 
ceeding 20 feet being recorded, the maximum observed being 40 feet a 
short distance to the east of Eilean na Gaoithe. Most of the islands are 
found in this part of the loch, Eilean na Gartaig being the largest, while 
Eilean na Gaoithe is remarkable for the long spit of sand and shingle 
which stretches from its northern point for a distance of nearly 100 
yards ; this spit is submerged when the water is high, but at the time 



THE FRESH- WATER LOCHS OF SCOTLAND. 163 

of the survey it rose some six inches above the surface of the water. 
The main basin is contained in the north-western portion of the loch, 
where the bottom falls in two places below the 100-feet level, separated 
by a slight shoaling of the water over a short interval. The larger of 
these two 100-feet areas near the centre of the loch is three-quarters of 
a mile in length, and the smaller, half a mile in length, approaches 
within less than half a mile from the north-west end, running com- 
paratively close to the south-eastern shore. It is curious to note that 
the maximum depth observed in each of these two areas is identical (122 
feet), though the two soundings are separated by an interval of about 
a mile ; the deepest water on the rise between the two areas is 83 feet. 
The slope along the north-eastern shore towards the north-west end of 
the loch is very steep; in one place a sounding of 91 feet was taken 
about 20 feet from the shore, and the cliff above was almost vertical and 
50 feet in height. The areas between the consecutive contour-lines, and 
the percentages to the total area of the loch, are as follows : 

to 25 feet 320 acres 49 '5 per cent. 

25 50 151 ,, 23-3 

50 75 67 10-4 

75 100 67 10-4 

Over 100 . 42 . 6 "4 



647 , 100-0 



Cam Loch was surveyed on August 27 and 28, 1902. The elevation 
of the lake-surface above the sea could not be determined, but when 
levelled by the Ordnance Survey officers on October 7, 1871, it was 
found to be 404-8 feet above sea-level. Judging from the level of the 
other lochs in the district at the end of August, 1902, its level was 
probably about a foot lower than that quoted, and the boatman stated 
that he had never seen the water more than two or three inches lower ; 
the highest drift-mark seen was 3*7 feet above the surface of the water 
on August 27, 1902. The temperature of the surface water was 56'2. 

Loch Veyatie (see Plate XXXVIII.). Loch Veyatie lies about half 
a mile to the west of the village of Elphin. It receives the water from 
the Cam Loch at its south-eastern end, where also the Amhainn a' 
Chnocain enters the loch ; the water is discharged at the north-western 
end of the loch by the Uidh Fhearna into the Fionn Loch. The ground 
around the loch is low, except where Cul Mor rises to a height of over 
2700 feet to the south-west, and Suilven (already referred to) to 
the north-west. The loch is over 4 miles in length, with a maximum 
breadth of nearly half a mile, the mean breadth being nearly a quarter 
of a mile (or about 400 yards). Its waters cover an area of about 593 
acres (or nearly one square mile), and it drains directly an area of over 



164 BATHYMETRICAL SURVEY OF 

11 J square miles, but since it receives the outflow from the Cam Loch 
and from Loch a' Mhiotailt, its total drainage area is about 46J square 
miles an area 50 times greater than that of the loch. Over 200 
soundings were taken, the maximum depth observed being 126 feet. 
The volume of water is estimated at 1,061,544,000 cubic feet (almost 
identical with the volume of the Cam Loch), and the mean depth at 
41 feet. The floor of Loch Veyatie is uneven, as is well shown in the 
sections on the map, with a few islands here and there along the shores, 
and some of the bays are filled with weeds. A continuous area exceeding 
25 feet in depth extends nearly from one end of the loch to the other, 




FIG. 31. LOCH VEYATIE, WITH SUILVEN IN THE DISTANCE. 

(Photograph by Rev. H. N. Bonar.) 



with an isolated sounding of 26 feet close to the south-eastern end off 
the promontory between the two inflowing streams, and with a small 
separate area having a maximum depth of 53 feet at the north-western 
end. Within the large 25 -feet area the bottom undulates in such a 
manner as to form two 50-feet areas and three 100-feet areas. Of the 
two 50-feet areas, the smaller but deeper one lies off the entrance to 
Loch a' Mhiotailt, and is three-quarters of a mile in length : it encloses 
the main 100-feet basin and the maximum depth of the loch (126 feet), 
winch was observed about 220 yards from the northern shore. The 
larger 50-feet area lies in the south-eastern portion of the loch, and is 



THE FRESH- WATER LOCHS OF SCOTLAND. 165 

two miles in length ; it encloses two small 100-feet basins with maximum 
depths of 113 and 103 feet respectively, separated by a rise of the bottom 
on which the depth is 82 feet. The areas between the consecutive 
contour-lines, and the percentages to the total area of the loch, are 
as follows : 

Oto 25 feet 230 acres 38 '8 per cent. 

25 50 ,, 215 36-2 

50,, 75 94 15-9 

75 100 38 6-4 

Over 100 , 16 . 2'7 



593 . 100-0 



Thus 75 per cent, of the lake-floor is covered by less than 50 feet of 
water. Loch Veyatie was surveyed on August 29 and September 8, 
1902. On commencing the survey 011 August 29, the elevation of the 
lake-surface was determined, by levelling from bench-mark, as being 
364-8 feet above the sea ; in the interval between the two days devoted 
to the survey the water rose to the extent of 15 inches, then gradually 
fell again, and on September 8 the elevation was found to be 365-6 feet 
above the sea. The soundings taken on the last-mentioned date have 
been corrected accordingly, in order to bring them into agreement with 
those taken on the earlier date. The boatman stated that the water in 
the loch was about its lowest level on August 29, 1902, and the highest 
drift-mark seen was 3 feet above the surface of the water on that date. 
The officers of the Ordnance Survey found the level of Loch Veyatie 
to be 365-7 feet above the sea on September 8, 1870. Temperature 
observations taken at 3.30 p.m. on September 8, 1902, indicated an 
almost uniform temperature throughout the waters of the loch, the 
readings at the surface and at a depth of 50 feet being identical (55'9), 
and at a depth of 100 feet 55-8. 

Loch a' Mhiotailt (see Plate XXXVIII.). Loch a' Mhiotailt 
(pronounced Vattle) lies immediately to the south-west of Loch Veyatie ; 
in fact, they may almost be looked upon as one loch, for after heavy 
rains there is a channel about 20 feet in length, 10 feet in breadth, and 
1 foot in depth connecting the lochs. When the water is low, however, 
the separation is complete, the barrier being formed by one of the basic 
dykes so numerous in this part of the gneiss : the rock is in places 
covered by a thin layer of sand. The ground around the loch rises 
steeply up to a height of 100 to 200 feet above the surface of the water, 
so that the loch is almost shut in, and only towards Loch Veyatie can 
any opening in the wall of rock be seen. Loch a' Mhiotailt is over 
half a mile in length from east to west, the maximum breadth exceeding 
a quarter of a mile, the mean breadth being about one-seventh of a mile, 



166 BATHYMETRICAL SURVEY OF 

or about 300 yards. Its waters cover an area of about 52 acres, and it 
drains an area of 1J square miles. Thirty soundings were taken, the 
maximum depth observed being 69 feet. The volume of water is 
estimated at 69,264,000 cubic feet, and the mean depth at 30 feet. 
The loch is irregular in outline, what may be called the body of the 
loch sending out a broad arm at right angles. The 25-feet area follows 
approximately the outline of the loch, and encloses two 50-feet basins, 
one towards the extremity of the arm containing the maximum depth 
of the loch (69 feet), the other centrally placed in the body of the loch 
with a maximum depth of 65 feet. The greatest depth observed between 
the two 50-feet basins was 38 feet. The areas between the consecutive 
contour-lines and the percentages to the total area of the loch are as 
follows : 

to 25 feet 21 acres 40 '2 per cent. 

25 50 22 42-7 

Over 50 , 9 17'1 



52 , -100-0 



Loch a' Mhiotailt was surveyed on September 8, 1902, when the 
water was at the same level as that in Loch Veyatie, viz., 365*6 feet 
above the sea. The soundings have been corrected in the same manner 
as the soundings taken in Loch Veyatie on the same date, so as to bring 
all the soundings into agreement with those taken in Loch Veyatie on 
August 29, 1902, when the surface of that loch stood at a level of 364-8 
feet above the sea. 

Fionn Loch (see Plate XXXVIII.). Fioiin Loch (or Loch Fewin 
or Fewn) lies about three miles to the east of Enard Bay and three- 
quarters of a mile to the north-west of Loch Veyatie, from which it 
derives the greater part of its water. Besides this, however, it drains 
the southern slopes of Suilven, which is little more than a mile distant 
from the loch. The great feature of the Fionn Loch is the existence of 
alluvial terraces surrounding the loch. The two lowest are the most 
extensive, together having an average breadth of 100 yards, their 
heights being about 20 and 30 feet above the surface of the loch. When 
the water stood at this level Loch Fionn must have been connected with 
Loch Veyatie, the difference in their levels, as observed by the Lake 
Survey, being only about 8 feet. This former loch must have formed 
a fine sheet of water some 7 \ miles in length, with a winding arm where 
is now Loch a' Mhiotailt. There is another still higher terrace seen to 
the north of Na Tri Lochaii. The Fionn Loch discharges its waters by 
the Kirkaig river, which forms the renowned Falls of Kirkaig about 
three-quarters of a mile below the loch. Very heavy rains fell on the date 
of the survey and on the previous days, and in the narrow parts of the 



THE FRESH- WATER LOCHS OF SCOTLAND. 167 

loch, especially in the one to the south of Creag a' Choire Mhoir, the 
current was so strong that the greatest difficulty was experienced in 
rowing the boat against it, though assisted by a strong north-west wind. 
The loch is nearly 2J miles in length, with a maximum breadth of oyer 
one-third of a mile (or about 600 yards), the mean breadth being about 
one-seventh of a mile (or about 250 yards). Its waters cover an area 
of about 209 acres (or nearly one-third of a square mile), and it drains 
directly an area of about 6J square miles, but since it receives the 
outflow from Loch Veyatie and the other lochs in the basin, its total 
drainage area is nearly 53 square miles an area 160 times greater 
than that of the loch. Over 100 soundings were taken, the maximum 
depth observed being 90 feet. The volume of water is estimated at 
185,510,000 cubic feet, and the mean depth at 20J feet. Fionn Loch 
is very irregular in outline, broads and narrows alternating with each 
other, and the contours of the bottom are correspondingly diversified. 
There is a long narrow tortuous area exceeding 25 feet in depth, 
extending from near the north-west end of the loch to north of the 
reedy bay where the stream from Na Tri Lochan enters, and about 
H miles in length; a short distance to the south-east is a second small 
25-feet area, with a maximum depth of 37 feet. The deepest water 
occurs in the wide part of the loch about half a mile to the south-east 
of the exit of the Kirkaig river, where there is a small area exceeding 
75 feet in depth, the maximum depth of 90 feet having been observed 
about 120 yards from the south-western shore. The areas between 
the consecutive contour-lines, and the percentages to the total area of 
the loch, are as follows : 

to 25 feet 153 acres 73 '0 per cent. 

25 50 49 23-5 
50,, 75 2 ,, 1-0 

Over 75 . 5 . 2*5 



209 ., 100-0 



This table shows how circumscribed the deep-water area is, 97 per cent, 
of the lake-floor being covered by less than 50 feet of water. The Fionii 
Loch was surveyed on September 16, 1902. The elevation of the lake- 
surface was determined, by levelling from bench-mark, as being 356-9 
feet above the sea ; when levelled by the officers of the Ordnance Survey 
on October 21, 1870, the elevation was found to be 357*1 feet above 
sea-level. The temperature of the surface water on September 16, 1902, 
was 53-0. 



168 BATHYMETRICAL SURVEY OF 



LOCHS OF THE POLLY BASIN. 

ONLY the two principal lochs in this basin (Lochan Gainmheich and 
Loch Skinaskink) were surveyed; Loch na Doire Seirbhe, Loch Lon 
na-h-TJamha, Loch Uidh Tarruingeach, and other smaller lochs had no 
boats on them at the time of the visit of the Lake Survey, and it was 
found impracticable to have boats transported to them. The waters of 
Lochan Gainmheich are discharged into Loch Skinaskink, thence by 
the river Polly into Loch Polly, an inlet of Enard Bay. 

Lochan Gainmheich (see Plate XXXIX.). Lochan Gainmheich lies 
about 1 miles to the north of Loch Lurgain and a quarter of a mile to 
the south-west of Loch Skinaskink, into which its waters are discharged 
by the Allt Lochan Gainmheich. The eastern end of the loch lies 
between Cul Mor and Cul Beag, and to the west An Stac rises to over 
2000 feet; Cul Beag and An Stac are connected by a ridge between 
Loch Lurgain and Lochan Gainmheich over 200 feet above the level of 
the loch, so that only towards Loch Skinaskink can an extensive view 
be obtained. The southern shore of Lochan Gainmheich is thickly 
wooded, but the northern and western shores are bare. The loch is 
naturally divided into a larger and deeper southern portion and a 
smaller and shallower northern portion, and it has been found con- 
venient to measure these two distinct portions separately. 

The southern portion is a mile in length from east to west, and 
nearly half a mile in maximum breadth, the mean breadth being over 
one-fifth of a mile. The area is about 135 acres, and it drains an area 
of nearly 2f square miles. Over 50 soundings were taken, and the 
maximum depth observed was 120 feet. The volume of water is 
estimated at 245,711,000 cubic feet, and the mean depth at nearly 42 
feet. This portion of Lochan Gainmheich is extremely simple in 
conformation, the bottom sinking down on all sides towards the deepest 
part, which is approximately centrally placed. The 50-feet area is 
about 1100 yards in length, and the 100-feet area about 400 yards in 
length, the maximum depth of 120 feet having been observed about 
130 yards from the southern shore. The areas between the contour- 
lines, and the percentages to the total area, are as follows : 






THE FRESH- WATER LOCHS OF SCOTLAND. 169 

to 50 feet 76 acres 56 -5 per cent. 

50,, 100 45 33-4 

Over 100 , 14 . lO'l 



135 100-0 



The northern portion is one-third of a mile in length, with a 
maximum breadth of a quarter of a mile and a mean breadth of one- 
sixth of a mile. The area is about 40 acres, and it drains directly an 
area of about 5 square miles, but, including the area draining into the 
southern portion, the total drainage area is about 7| square miles. 
Over 20 soundings were taken, the maximum depth observed being 59 
feet. The volume of water is estimated at 43,274,000 cubic feet, and 
the mean depth at 24 J feet. The floor of this portion of Lochan 
Gainmheich is not so perfectly regular in conformation as that of the 
southern portion. There is an isolated sounding of 27 feet opposite the 
outflow, and within the 25 -feet area the bottom is slightly undulating ; 
the maximum depth of 59 feet was observed about 120 yards from the 
southern shore, and this was the only sounding exceeding 45 feet in 
depth. 

Lochan Gainmheich was surveyed on September 10, 1902, the 
surface of the water being 251*5 feet above sea-level; when levelled by 
the Ordnance Survey officers on August 26, 1870, the elevation of the 
lake-surface was 251'1 feet above the sea. The highest drift-mark seen 
was 3-4 feet above the surface of the water on September 10, 1902. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch at 4 p.m. on September 10, 1902, gave the 
following results : 

Surface 55'5 Fahr. 

50 feet 55-3 

110 54-0 

Loch Skinaskink (see Plate XXXIX.). Loch Skinaskink (or 
Shianas-kaig) is a large loch lying about 2J miles to the east of Enard 
Bay, into which it drains by the river Polly. It is one of the most 
interesting lochs visited by the Lake Survey, because of the extreme 
irregularity both of its outline and of the conformation of the lake-floor. 
So irregular is the outline of the loch that it has over 17 miles of 
shore-line. It is a splendid trout loch, but preserved, and the islands 
are covered with birch woods where deer are often found ; the largest 
island is Eilean Mor, near the centre of the loch, and there are two 
islands named Eilean Dubh, one near Eilean Mor in the centre of the 
loch, and the other in the north-eastern arm. The ground to the west 
and north of the loch is low, but to the east and south rise Cul Mor 
(2700 feet), Cul Beag (2500 feet), and An Stac (2000 feet). There is a 



170 BATHYMETRICAL SURVEY OF 

sluice at the lower eud of Loch Uidh Tarruingeach (through which the 
discharge from Loch Skinaskink passes into the river Polly) to control 
the outflow of the water, and by its means the average level of the 
loch has been raised about 3 feet. The length of Loch Skinaskink, 
measured from the south-eastern end near Lochan Gainmheich to the 
north-western arm near Loch na Moine Moire, is over 3 miles, and the 
maximum breadth is over a mile, the mean breadth being two-thirds 
of a mile. Its waters cover an area of over 2 square miles, and it 
drains directly an area of nearly 8 square miles, but since it receives 
the outflow from Lochan Gainmheich its total drainage area is over 
15J square miles an area only 7J times greater than the area of the 
loch. Nearly 400 soundings were taken, the maximum depth observed 
being 216 feet. The volume of water is estimated at 3,518,305,000 
cubic feet, and the mean depth at 60^ feet. Reference has been made 
to the irregularity of the floor of Loch Skinaskink, and the contour-lines 
on the map have a fanciful resemblance to an intricate maze. There 
are three main basins, which may be briefly described, viz. (1) one 
embracing nearly the whole of the main body and surrounding Eilean 
Mor; (2) one lying in the north-eastern arm of the loch; and (3) one 
lying in the north-western arm of the loch. 

(1) The first basin is the largest and deepest. In it the 25-feet and 
50-feet contour-lines follow approximately the outline of the shore, 
running into all the large bays (except that the 50-feet line does not 
enter the bay south of Camas nam Fiadh). The 100-feet area has a 
very sinuous outline, almost surrounding Eilean Mor, and sending a 
large tongue into the western arm of the loch. There are two areas 
exceeding 150 feet in depth one to the south of Eilean Mor enclosing 
the deepest part of the loch, the other to the west and north-west of 
that island extending to the north of Eilean Dubh. The 200-feet area 
is small, based on soundings of 204 and 216 feet, the last-mentioned 
the deepest sounding in the loch lying about 350 yards to the south of 
Eilean Mor. The great feature of this basin is the occurrence of two 
hills to the west of Eilean Mor ; the one nearest the island is covered by 
38 feet of water, the depth between it and the island being 70 feet, 
and between it and the south-western shore exceeding 100 feet; the 
other is covered by 41 feet of water, the depth around it being from 
100 to 150 feet. 

(2) The second basin in the north-eastern arm is much smaller, and 
the 25-feet and 50-feet contour-lines are continuous with those of the 
preceding basin. The 100-feet area is centrally placed in this arm, and 
has a maximum depth of 137 feet. A small isolated 25-feet area lies to 
the north-west of Eilean Dubh in this arm, with a maximum depth of 
34 feet. 

(3) The third basin in the north-western arm is the smallest and 
shallowest of the three, and is cut off from the main basin by very 






THE FRESH- WATER LOCHS OF SCOTLAND. 171 

shallow water. The 25-feet contour-line follows approximately the 
outline of the arm, and the 50-feet area is considerable, the maximum 
depth being 66 feet in the eastern part of the basin. 

The areas between the consecutive contour-lines, and the per- 
centages to the total area of the loch, are as follows : 

to 50 feet 672 acres 50 '2 per cent. 

50,, 100 422 31-7 

100,, 150 171 127 

150,, 200 68 5-0 

Over 200 , 5 , 0'4 



1338 ,, 100-0 



Loch Skinaskink was surveyed on September 19 to 23, 1902. The 
elevation of the lake-surface above the sea on commencing the survey 
on September 19, 1902, was determined, by levelling from bench-mark, 
as being 245*1 feet; when levelled by the Ordnance Survey officers on 
August 13, 1870, the elevation was 242-7 feet above sea-level. The 
highest drift-mark seen was 3J feet above the surface of the water. 

Temperature Observations. Temperature observations taken in the 
deepest part of the loch at 4 p.m. on September 20, 1902, gave the 
following results : 

Surface .. .. ... 54 '2 Fahr. 

10 feet 54-2 

25 54-0 

50 54-0 ,. 

100 ,, 53'3 ,, 

125 50'l 

150 ,, .. .. 50'0 ,, 

170 , '. 49-6 

This series shows a range of temperature amounting to 4 0> 6, the greatest 
fall being one of 3*2 between 100 and 125 feet. 



172 BATHYMETRICAL SURVEY OF 



LOCHS OF THE GARVIE BASIN. 

THE lochs in this basin form a connected series, Loch Lurgain flowing 
through Loch Bada na h-Achlaise (which was not sounded) into Loch 
Bad a' Ghaill, thence by the Abhuinn Owskeich into Loch Owskeich, 
which flows through the little Loch Garvie into Garvie Bay, an inlet 
of Enard Bay. The lochs contain salmon and trout, but the fishing is 
preserved. 

Locli Luryaiii (see Plate XL.). Loch Lurgain lies about two miles 
to the south of Loch Skinaskink, and 3J miles south-east of Eiiard 
Bay. The scenery around the loch is very fine, the serrated crest of 
An Stac and the great pyramid-shaped mass of Cul Beag forming the 
high ground to the north, while to the south rise Beinn Eun and 
An t-Sail. The loch is crescent-shaped, with the concave side turned 
towards the south. Very fine cliffs are formed in places, especially on 
the southern shore to the west of the large islands, where for some 
distance the cliffs are overhanging, and in one place there is a small 
cave or recess in which 20 feet of water was found. On the opposite 
northern shore are huge angular blocks which have slipped down from 
above, one on top of the other, forming fine natural chambers. Loch 
Lurgain is nearly 4 miles in length, the maximum breadth being over 
half a mile, and the mean breadth one-third of a mile. Its waters 
cover an area of 1J square miles, and it drains an area ten times 
greater, or 12J square miles. Nearly 200 soundings were taken, the 
maximum depth observed being 156 feet. The volume of water is 
estimated at 2,139,752,000 cubic feet, and the mean depth at 61 feet. 
The loch is divided into two basins by the large islands and the shallow 
water between them. The eastern basin is the larger and deeper, and 
quite simple in conformation. The 50-feet area is 2 miles in length, 
extending from the narrow part of the loch at the south-east end to 
north of the largest island. The 100-feet area is nearly 1J miles in 
length, approaching to within less than a quarter of a mile from the 
eastern point of the largest island. The 150-feet area is small and 
centrally placed, and encloses the maximum depth of the loch (156 
feet). In the eastern part of this basin are several rocky islets rising 
from deep water to 1 to 3 feet above the surface. The western basin 



THE FRESH- WATER LOCHS OF SCOTLAND. 173 

is not quite so simple in conformation as the eastern one, the 100-feet 
area having a central constriction in its outline with deeper water on 
both sides. The 50-feet area is 1J miles in length, approaching to 
within 200 feet of the western end of the loch. The 100-feet area is 
nearly a mile in length, with a depth of 103 feet in the central con- 
striction, deepening to 130 feet to the west, and 146 feet to the east, 
of the constriction. The areas between the consecutive contour-lines, 
and the percentages to the total area of the loch, are as follows : 

to 50 feet 352 acres 43 '6 per cent. 

50,, 100 306 ,, 38-0 

100,, 150 145 18-0 
Over 150 , 4 , 0*4 



807 100-0 



Loch Lurgain was surveyed on September 5 and 9, 1902. The 
elervation of the lake-surface above the sea could not be determined, 
but when levelled by the Ordnance Survey officers on August 9, 1870, 
the level was found to be 173-0 feet. 

Temperature Observations. Temperature observations were taken 
in the deepest part of the loch at 3 p.m. on September 9, 1902, with 
the following results: 

Surface 56'l Fahr. 

50 feet 55-5 ,, 

100 , 52-0 

140 50-3 

This series shows a range of temperature amounting to 5 0- 8, there being 
a fall of 3-5 between 50 and 100 feet. The range was greater than 
that observed in any other loch in the district, even in Lochs Assynt, 
Skinaskink, and Bad a' Ghaill, which are all deeper than Loch Lurgain. 

Lock Bad a' Ghaill (see Plate XLI.). Loch Bad a' Ghaill (or 
Baddegyle) lies immediately to the north-west of Loch Lurgain, with 
which it is connected by the little Loch Bada na h-Achlaise, and about 
1J miles to the south-east of Enard Bay. The ground to the north and 
west is comparatively low, An Stac and An t-Sail rising to the east and 
south. The loch is over 2 miles in length, with a maximum breadth of 
three-quarters of a mile, the mean breadth being nearly half a mile. 
Its waters cover an area slightly exceeding one square mile, and it 
drains directly an area of 4| square miles, but since it receives the 
outflow from Loch Lurgain its total drainage area is over 17 square 
miles. Over 150 soundings were taken, the maximum depth observed * 
being 180 feet. The volume of water is estimated at 1,767,582,000 
cubic feet, and the mean depth at 62 feet. Loch Bad a' Ghaill is cut 



174 BATHYMETRICAL SURVEY OF 

into two deep basins by the shoaling of the bottom between the penin- 
sula of Rudha Dubh on the southern shore and the island opposite to it 
towards the northern shore, but even here there is a depth near the 
centre of 72 feet, so that the 25-feet and 50-feet areas are continuous 
from end to end of the loch. The 25-feet contour-line follows approxi- 
mately the outline of the loch ; the 50-feet contour is extremely sinuous, 
in some places following the outline of the loch and in other places, 
especially in the central part of the loch, being far removed from the 
shore-line. Of the two 100-feet basins the south-eastern one is the 
larger and deeper, being over three-quarters of a mile in length, and 
widest towards the centre of the loch, narrowing on approaching the 
south-eastern prolongation. The maximum depth of the loch (180 feet) 
was observed towards the south-eastern end of this basin, and about 
200 yards from the north-eastern shore. The north-western 100-feet 
basin is less than half a mile in length, with a maximum depth of 
153 feet. Some of the lines of soundings show minor undulations of 
the lake-floor, and in one case towards the north-western end a sounding 
of 20 feet was recorded about 250 yards from the southern shore with 
a depth of 80 feet between it and the shore ; this shallow sounding may 
possibly be connected with the shallow water surrounding the large 
island lying to the south-west. There are indications of moderately 
steep slopes, especially along the south-western shore, where soundings 
exceeding 40 feet were recorded in various places close inshore. The 
areas between the consecutive contour-lines, and the percentages to 
the total area of the loch, are as follows : 

to 50 feet 296 acres 45 '1 per cent. 

50,, 100 239 ,, 36-5 

100., 150 ,, 100 15-3 

Over 150 , 21 3'1 



656 100-0 



Loch Bad a' Ghaill was surveyed on September 18, 1902; the 
elevation of the lake-surface above the sea could not be determined. 

Temperature Observations. Temperature observations taken at 
5 p.m. in the deepest part of the loch gave the following results: 

Surface .. 54 '5 Fahr. 

50 feet r>4v> 

100 50-5 ,, 

170 50'0 

This series shows a constant temperature down to 50 feet, then a fall of 
4 between 50 and 100 feet, the extreme range being 4-5. 

Loch Owskeich (see Plate XLL). Loch Owskeich (or Oiskaig) lies 
about a mile to the north-west of Loch Bad a' Ghaill, to which it is 



THE FRESH- WATER LOCHS OF SCOTLAND. 175 

connected by the Abhuinn Owskeich, and half a mile to the south of 
Enard Bay, into which its waters are discharged by the river Garvie. 
The ground around the loch is low, especially to the north and west. 
The loch is over 1J miles in length, with a maximum breadth of three- 
quarters of a mile, the mean breadth being less than half a mile. Its 
waters cover an area of about 420 acres, or two-thirds of a square mile, 
and it drains directly an area of about 3 square miles, but since it 
receives the outflow from Lochs Bad a' Ghaill and Lurgain its total 
drainage area is about 20 square miles an area thirty-one times 
greater than that of the loch. Over 100 soundings were taken, the 
maximum depth observed being 153 feet. The volume of water is 
estimated at 845,809,000 cubic feet, and the mean depth at 47 feet. 
Loch Owskeich forms a simple basin, but the deep water approaches 
very close to the south-eastern shore, off which the slopes are steep and 
in striking contrast to the gentle slopes at the north-west end of the 
loch. A sounding of 90 feet was recorded only 100 feet, and a sounding 
of 120 feet only 200 feet, from the eastern shore, and the maximum 
depth of the loch (153 feet) was observed about 300 yards from that 
shore. At the opposite end of the loch the 25-feet contour-line is 
distant 300 yards, and the 50-feet contour half a mile, from the north- 
western shore. The 50-feet area is nearly a mile, and the 100-feet area 
nearly three-quarters of a mile, in length. In the shallower water 
towards the outflow one or two slight undulations of the lake-floor 
were observed. The areas between the consecutive contour-lines, and 
the percentages to the total area of the loch, are as follows : 

Oto 50 feet 280 acres 66 '3 per cent. 

50 ,, 100 82 19-7 

100 150 57 13-7 

Over l.>0 . I 0'3 



420 100-0 



Loch Owskeich was surveyed on September 18, 1902 ; the elevation 
of the lake-surface above the sea could not be determined, but when 
levelled by the Ordnance Survey officers on July 8, 1870, it was found 
to be 71-9 feet above sea-level. 

Temperature Observations. Temperature observations taken at 
4 p.m. on September 18, 1902, in the deepest part of the loch gave the 
following results : 

Surface .. 54'8 Fahr. 

50 feet .. 54 *2 ? , 

100 53-7 

130 ,, .. 50-8 

This series shows a range of 4, the greatest fall being one of 2-9 
between 100 feet and the bottom. 



176 



BATHYMETRICAL SURVEY OF 



The details regarding the lochs in the Inver, Roe, Kirkaig, Polly, 
and Garvie basins are collected together in the following table for 
convenience of reference and comparison. Where the elevation above 
the sea was not determined by levelling from bench-mark, the 
approximate elevation is given in brackets; in the case of Lochs 
Urigill, Cam, Lurgain, and Owskeich, the Ordnance Survey level is 
given with an indication of the date when levelled. 

From this table it will be seen that in the twenty lochs under 
consideration, 2540 soundings were taken, and that the aggregate area 
of the water-surface is over 12J square miles, so that the average 
number of soundings per square mile of surface is 200. The aggregate 
volume of water contained in the lochs is estimated at about 20,355 
millions of cubic feet. The area drained by these lochs is about 150J 
square miles, or twelve times the area of the lochs. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



& 



= 

I !k 



HI 



ui 
fll 



I 2 



50 



feli 



- I 



"Nr-t 





T -^ 



t^'T^t^-t Ci^ t--i--r: v :i^C 
i - - - -M rt 71 '-: i^ x ic -H 






l!l 



! f 

J J 



ttS*S5^-'i-O^-S:.2 d ji3e3S 

<!js<;c8i= c5 D3>S&. s ooijwo 



177 



i- 

S2 
- a 



-i 

. T3 



r ?- s 



o o 

J3fg 

00 t^ -g g 



T3 *t^ O 
98 3) O^ 

51 SI 

SF s,cj 

= r - - = 

nil 

^iTz 

^s- 

I 50 o 1 

silt 



2- g^ 

C ^3 * O 
"J3 fl 



r tt -- = 

s a S^ 

11^ 
"ill 

11^ 



178 BATHYMETRICAL SURVEY OF 



NOTES ON THE GEOLOGY OF THE ASSYNT DISTRICT. 

By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. With 
Geological Map (Plate XLIL). Published by permission of the 
Director of the Geological Survey. 

From a geological point of view, the Assynt district is one of 
the most interesting in the north-west Highlands. The various rock 
formations which enter into the geological structure of the region are 
there splendidly developed, and the evidence in proof of those great 
terrestrial displacements of post-Cambrian date may be studied in 
detail in the mountainous region that runs southward from Glas Bheinn 
by Ben More Assynt and Breabag to the Cromalt Hills. 

Beginning with the Archaean gneisses (gt on map), which may be said 
to form the foundation-stones of that region, they are unquestionably 
older than the succeeding great development of Torridon Sandstone 
and overlying Cambrian strata. On referring to the geological map, 
it will be seen that they occupy a belt of ground from 6 to 9 miles broad, 
extending along the western coast-line between Enard Bay and Stoer, 
thence inland to the base of the grand escarpment of Torridon Sand- 
stone that stretches southwards from Quinag to the Coigach mountains. 
These crystalline gneisses give rise to a type of scenery that is charac- 
teristic of a large part of the western seaboard of Sutherland and Ross, 
which seems to be typical of Archaean areas. Bare rounded knolls and 
bosses of grey gneiss follow each other in endless succession, and in the 
hollows there are numerous pools and lochs occupying rock-basins. The 
whole tract occupied by these crystalline gneisses is singularly destitute 
of drift. The rocky knolls do not rise much above one general level, 
which does not as a rule exceed a few hundred feet in height, save near 
the base of Quinag, Canisp, and Suilven, where the elevation of the old 
gneiss plateau is about 1000 or 1250 feet. 

The Archaean rocks of the Assynt district, west of the great 
escarpment of Torridon Sandstone, consist largely of pyroxene gneisses 
and ultrabasic rocks (pyroxenites and hornblendites), which still show 
in a marked degree their original characters. Their behaviour in the 
field and their appearance under the microscope have led to the 
conclusion that they have affinities with plutonic igneous products. 
All over that district, where the original characters have not been 
effaced by later mechanical stresses, it is possible to trace the imperfect 
separation of the ferro-magnesian from the quartzo-felspathic con- 
stituents, the gradual development of mineral banding, and the net-like 
ramifications of acid veins (pegmatite) in the massive gneiss. Whatever 
be the origin of the mineral banding in these Archaean gneisses, it is 



THE FRESH- WATER LOCHS OF SCOTLAND. 179 

certain that they possessed this banding and were thrown into gentle 
folds before the intrusion of the later dykes. 

On referring to the map showing the surface geology of the Assynt 
district, it will be seen that the Archaean area is traversed by narrow 
dykes of igneous material (B G on map) trending west-north-west or 
north-west. In certain belts they occur in great numbers, and their 
intrusive character is clearly displayed. The dominant types in 
the Assynt district comprise ultrabasic rocks (peridotite) and basic, 
including dolerite and epidiorite. These dykes frequently form pro- 
minent features in the landscape, sometimes giving rise to ridges and 
sometimes to clefts or " slacks " in the midst of the surrounding gneiss. 

A further important feature in the history of the Archaean gneiss 
remains to be noticed, for, after the uprise of the great series of 
intrusive dykes, the whole region was subjected to mechanical stresses 
that profoundly affected the pyroxenic gneisses and the dykes which 
traverse them. These lines of movement may be described as lines of 
shearing or disruption lines, which trend in certain definite directions, 
and give rise to molecular re-arrangement of the minerals and the 
development of newer foliation both in the gneiss and in the dykes. 
The gneisses are thrown into sharp folds, and are traversed by zones or 
belts of secondary shearing, in which the pyroxenic rocks are converted 
into bio tit e and hornblende gneisses. In like manner, the basic and 
ultrabasic dykes appear frequently as phacoidal masses in the shear 
zones, and where the latter coincide more or less with the original 
trend of the dykes, or cross them, then the peridotite and epidiorite 
intrusions are changed into talcose schist and hornblende schist 
respectively. A glance at the Geological Survey 1-inch maps of the 
Assynt district (Sheets 107 and 101) shows the great number of these 
lines of movement. Further reference will be made to these features 
in connection with the rock-basins of that district. At present it is 
important to remember that all these movements took place before the 
deposition of the Torridmi Sandstone. 

This undulating plateau of Archaean gneiss was originally covered 
by a vast pile of sandstones, conglomerates, and shales (Torridonian, 
t on map), which has been largely removed by denudation. The 
unconformability at the base of the Torridon Sandstone represents a 
vast interval of time, during which the old land-surface of Archaean 
gneiss was carved into hill and valley. On the north-west slope of 
Quinag a remnant of this ancient topography is still to be found, where 
a hill of crystalline gneiss rises to a height of 800 feet in the overlying 
sandstone. One of the striking features in the landscape of that 
region is the great western escarpment of Torridon Sandstone, reaching 
in places an elevation of 1000 feet above the Archaean plateau. That 
cliff is not continuous, for the sandstones on Quinag north of Loch 
Assynt cannot be traced without a break to those of Cul Mor and Cul 



180 BATHYMETRICAL SURVEY OF 

Beag and of the Coigach mountains beyond. Though at the base there 
is sometimes a local breccia that varies in character in accordance with 
the underlying rocks, this pile of sediment mainly consists of a 
succession of false-bedded grits and sandstones, with scattered pebbles 
derived from formations which do not now occur in the west of 
Sutherland and Ross. On Quinag and Beinn Gharbh the sandstones 
have a gentle dip to the south of east, but on Suilven the strata are 
horizontal, or nearly so. They attain a thickness of several thousand 
feet, for in the Coigach mountains they rise from the shores of Loch 
Broom to a height of about 2400 feet. 

Overlying the Torridon Sandstone come the various subdivisions of 
the Cambrian formation, comprising the basal quartzite (a 1 on map), 
pipe-rock (a 2 ), fucoid beds (a 3 ), serpulite grit and limestone (a 4 ). The 
detailed mapping of that region has proved that the Cambrian strata 
are separated from the Torridon Sandstone by a marked uncon- 
formability, It represents an interval of time during which the 
Archaean floor and overlying Torridonian sediments were exposed to 
denudation; a vast thickness of strata was removed, and in places the 
Archaean gneisses were laid bare. Hence we find in the undisturbed 
area clear evidence of the double unconformability of the Cambrian 
quartzites on the Torridon Sandstone and Archaean gneiss. This 
important geological feature is well displayed on the north slope of 
Beinn Gharbh, south of Loch Assynt. The age of these sediments 
has been proved by the discovery of trilobites and other organisms, 
characteristic of the lower division of the Cambrian system, in the 
fucoid beds of Sutherland and Ross. Fragments of these trilobites 
have been found in this member of the series at BLnockan and on the 
north shore of Loch Assynt. 

On referring to the map, it will be seen that to the west of the 
band of limestone (a 4 ) extending from Inchnadamph to Knockan, the 
Cambrian quartzites and fucoid beds have been traced across the sheet 
from Loch Gainmheich to Strath Kanaird. On the eastern slopes of 
Quinag, Canisp, and Cul Mor, the white quartzites form a thin cake 
on the underlying Torridon Sandstone, which on some of the lofty 
peaks is isolated by denudation. The quartzites dip at a higher angle 
than the sandstone, and on descending the hill slopes the former pass 
transgressively across bed after bed of the sandstone, and rest succes- 
sively on lower members of the Torridon Sandstone. 

One of the remarkable features of the Assynt district is the series 
of intrusive igneous rocks of later date than the Cambrian limestone 
and older than the post-Cambrian movements. In the undisturbed 
area west of the great post-Cambrian displacements, they cover con- 
siderable areas on Beinn Gharbh, south of Loch Assynt, where they 
appear as sills in the Torridon Sandstone or Cambrian quartzite. 
These sills can be traced round the western slopes of that hill, as well 



THE FRESH- WATER LOCHS OF SCOTLAND. 181 

as round the escarpments of Suilven and Canisp. But in the displaced 
masses, east of a line extending from Inchnadamph to Knockan, the 
intrusive rocks of this series have a much larger development and 
greater variety. They appear at intervals over a tract measuring 12 
miles from north to south, and from 5 to 6 miles from east to west. 
The largest of these masses extends from Ledmore and Cnoc na Sroine 
eastwards by Aultnacallagach towards Cnoc Chaoruinn, and another 
important sheet runs north from Loch Ailsh to Loch Sail an Ruathair. 
But throughout the mountainous region of Glas Bheinn, Ben More 
Assynt, and Breabag these igneous rocks appear as sills in the" various 
thrust-masses, restricted generally to certain definite horizons. A 
glance at the map will show that they occur at the base of the Cambrian 
quartzite, in the basal quartzite, in the pipe-rock, in the fucoid beds, 
and also in the limestone. The mapping of these intrusive sheets has 
shown the complicated character of the geological structure of that 
region. The petrographical characters of these igneous materials have 
been studied by Mr. Teall, and are of special interest. They comprise 
the plutonic mass of Cnoc na Sroine and Loch Borralan, and the 
numerous sills and dykes that traverse the Torridonian and Cambrian 
sediments. The former seems to have resulted from the consolidation 
of alkaline magmas rich in soda ; at the one end of the series there is 
the quartz-syenite of Cnoc na Sroine, and at the other the basic augite- 
syenite, nepheline-syenite, and borolanite. The sills and dykes include 
two well-marked types viz., hornblende-felspar rocks, and felsites with 
alkali felspar and aegirine. 

Before proceeding to the description of the eastern or Moine schists 
(in on map), reference must be made to those terrestrial movements 
which affected that region in post-Cambrian time, whereby the 
Cambrian rocks were piled on each other, and huge slices of the floor 
of Archaean gneiss with the overlying Torridonian and Cambrian 
sediments were driven westwards and made to override the underlying 
piled-up strata. The structure is admirably shown in the horizontal 
section extending from Quinag to the river Cassley, placed below the 
map, showing the surface geology of the Assynt district. On referring 
to that section, it will be seen that at its western limit on Quinag, 
where the rocks are undisturbed, the Torridon Sandstone rests on a 
highly eroded platform of Archaean gneiss, being itself unconformably 
overlaid in turn by the Cambrian quartzites, fucoid beds, and serpulite 
grit (3, 4, 5, and 6 in section). In the valley of the Skiag, north of 
Loch Assynt, the first disruption line or thrust-plane is met with, above 
which lie various members of the Cambrian system, chiefly the fucoid 
beds, serpulite grit, and limestone, with their accompanying intrusive 
sheets of igneous material, all of them being driven together by minor 
thrusts or reversed faults or folds. 

Crossing the limestone plateau at Achumore to the western base 



182 BATHYMETRICAL SURVEY OF 

of Glas Bheinn, we encounter the Glencoul thrust (T in section), the 
first of the series of powerful displacements in the Assynt region. 
Overlying this plane there is a mass of Archaean gneiss, covered un- 
conformably by both divisions of the Cambrian quartzite with their 
characteristic igneous sills. Along the western slope of Glas Bheinn 
the quartzites are inverted, but the sequence can be interpreted by 
means of the subdivisions of the pipe-rock, based on the characters 
of the worm-casts from which that zone derives its name. Eastwards 
we find the Poll an Droighinn thrust (T' in section), and still further 
east, beyond Loch Cuaran, the Ben More thrust (T" in section). By 
means of these displacements, additional slices of the Archaean floor 
with the overlying Cambrian sediments and intrusive sheets have been 
driven westwards like the materials above the Glencoe thrust-plane. 
The visitor to that district may study the relations of the Ben More 
thrust-plane and the materials above and below it on the southern 
slope of that mountain in the Beallach (pass) of Coniveall. A con- 
siderable thickness of Torridon Sandstone there intervenes between the 
Archaean gneiss and the Cambrian quartzites, which does not appear 
in the line of section further north between Quinag and the river 
Cassley. Indeed, on Ben More Assynt, the double unconformability 
of the Cambrian quartzite on the Torridon Sandstone and the Archaean 
gneiss is well seen. In the deep corries on the south side of Ben More 
Assynt, the observer finds a great development of the Lewisian gneiss 
with its dykes of epidiorite, forming a rocky slope about 1000 feet high, 
which presents many of the characteristic features of the old Archaean 
floor west of Quinag. Eastwards again, towards the river Cassley, 
beyond the Cambrian quartzites, fucoid beds, serpulite grit, and 
limestone, appears the Moine thrust, which brings forward a great 
succession of crystalline schists (Moine schists, M in section), to which 
reference will immediately be made. 

One of the romantic features of the geology of the Assynt region is 
the isolation by denudation of materials overlying the Ben More thrust- 
plane. Two outliers of this nature occur west of Breabag, on Beinn 
nan Cnaimhseag and Beinn an Fhuarain, where slices of Torridon 
Sandstone and basal Cambrian quartzite overlie Cambrian limestone. 
Indeed, in the more southerly mass (see map) a small core of Archaean 
gneiss with an intrusive dyke of epidiorite appears in the midst of the 
younger formations. These outliers clearly point to the original 
westward extension of the materials overlying the Ben More thrust- 
plane having been separated from the main mass east of Breabag by 
prolonged denudation. It is worthy of note that, though the structure 
of the disturbed area in the mountainous region of Assynt is highly 
complicated, still by the zonal mapping of the various rock groups, 
the relations of the displaced materials can be satisfactorily determined. 

The Moine thrust (T IV in section) is the most easterly of the great 



THE FRESH- WATER LOCHS OF SCOTLAND. 183 

post-Cambrian displacements that affected that region, the outcrop 
of which is somewhat remarkable. On referring to the geological map, 
it will be seen that it can be traced from Loch nan Caorach and Gorm 
Loch Mor east of Glas Bheinn, southwards along the eastern base of 
the Ben More group of mountains to Loch Ailsh, thence across the 
Oykell to the Cromalt hills. Here the outcrop of the thrust-plane 
changes its course, and runs west along the base of these hills to 
Knockan, a distance of 6 miles, whence it runs southwards to Strath 
Kanaird. It will thus be seen that there is an extraordinary overlap 
of the Moine thrust-plane along the base of the Cromalt hills, for it 
passes transgressively across the Ben More thrust-plane and all 
underlying thrusts till the materials overlying it rest directly on the 
undisturbed Cambrian strata south of Knockan. 

Near the Moine thrust the new structures resulting from the post- 
Cambrian movements are well developed. The lenticles of Lewisian 
gneiss and pegmatite are sheared and rolled out, the former passing 
into flaser gneiss and schist, and ultimately into a banded platy schist, 
while the latter show fluxion structure with felspar " eyes " like 
rhyolites. The Torridon Sandstone and Cambrian quartzites, the 
fucoid beds and intrusive igneous sheets, are likewise sheared and 
rolled out, the new divisional planes being more or less parallel to that 
of the Moine thrust. Indeed, such is the transformation effected by 
these movements on the crystalline rocks and overlying sediments, 
that it is often difficult to determine the original characters of the 
component members. It is noteworthy, however, that all the crushed 
or mylonised rocks near the Moine thrust show a characteristic striping 
on the divisional planes due to orientation of the constituents in the 
direction of movement. 

The strata overlying the Moine thrust-plane and stretching east- 
wards down the Cassley and the river Oykell and across the Cromalt 
hills are remarkably uniform in character. They consist to a large 
extent of flaggy quartzose schists, with partings and bands of mica- 
schists and occasional intrusive sheets or sills of igneous material which 
have a common foliation with the schists. The matrix of the quartz- 
schists is holo-crystalline and forms a granulitic mosaic, which is 
perhaps the characteristic feature of the group. Occasionally "eyes" 
of felspar appear in the schists, when the rocks might be described as 
flaser schists. There can be little doubt that the Moine schists are to 
a large extent, if not wholly, altered sediments, the age of which is 
still uncertain. Any one who has examined the Archaean rocks in 
the undisturbed area west of the Torridon Sandstone escarpment, has 
no difficulty in distinguishing the pyroxenic gneisses and intrusive 
dykes from the quartz-schists and mica-schists of the Moine series. 
These broad lithological distinctions have been of great service in 
interpreting the history of the glaciation of that region. 



184 BATHYMETRICAL SURVEY OF 

The Assynt district furnishes impressive evidence of denudation by 
the removal of a vast covering of Torridon Sandstone, by the persistent 
eastward recession of that escarpment, by the stripping off of the 
materials overlying the successive thrust-planes, and also by the 
development of the present drainage system. It is a remarkable fact 
that south of the mountainous region of Assynt the watershed lies to 
the east of Cul Mor, Cul Beag, and the Coigach mountains in the less 
elevated platform of the Moine schists. It is evident that the present 
drainage system originated at a remote geological period, when the 
eastern or Moine schists extended far to the west of their present 
limits, and were arranged in the form of a dome round the displaced 
masses which now form the mountainous region of Assynt. It is highly 
probable, also, that before the glacial period the land stood relatively 
higher than at present, and that the rivers on the west side of the 
watershed occupy consequent valleys which extended far to the west 
of the present coast-line. 

Everywhere throughout the Assynt district, and especially in the 
mountainous region extending from Glas Bheinn to the Coigach area 
and over the plateau of Archaean gneiss, there is conclusive evidence of 
intense glaciation. Perhaps the most striking feature of the glacial 
phenomena of Assynt is the evidence pointing to the conclusion that 
during the maximum glaciation the ice-shed did not coincide with the 
existing watershed. From an examination of the striae indicating the 
direction of the ice-flow, and from the distribution of boulders, it 
appears that the ice-parting lay to the east of the present watershed. 
Indeed, the ice must have accumulated to a great thickness on the less 
elevated plateau occupied by the Moine schists east of the Ben More 
Assynt range and east of the Coigach mountains. 

The general movement of the ice at great elevations in this district 
was in a westerly direction, sometimes to the north and sometimes 
south of that point. For example, on Glas Bheinn, on one of the 
exposures of Archaean gneiss, at a height exceeding 2000 feet, the 
striae point W. 5 N. Again, on Beallach an Uidhe, between Glas 
Bheinn and Beinn Uidhe, at an elevation of about 2000 feet, the 
direction is west-south-west. East of Inchnadamph, on the quartzite 
of Beinn an Fhurain, between the 2000- and 2250-feet contour-lines, 
the striae run north of west. In the lofty pass crossing the Ben More 
range, that leads into Corrie Mhadaidh, at a level of 2750 feet, the 
direction is W. 10 S. or W.S.W. In like manner, on the long ridge 
of Breabag that runs northward from the Beallach of Coniveall, the 
average height of which is over 2000 feet, splendidly striated surfaces 
have been recorded which indicate an ice-movement in a westerly 
direction. 

Passing westwards to the mountains north and south of Loch 
Assynt, we find similar evidence of a westerly movement during the 



THE FRESH- WATER LOCHS OF SCOTLAND. 185 

maximum glaciation. On Quinag, at an elevation of 1750 feet, the 
striae point W. 5 N., and on Beinn Garbh near the top, about the 
1500-feet contour-line, the direction varies from W. 10 S. to W.S.W. 
On the eastern slope of Canisp, between the 1250- and 1500-feet 
contour-lines, on polished surfaces of quartzite, the striae point north 
of west, indicating an ice-movement up the slope in the direction of 
the Archaean plateau. On the flanks of Suilven, below the limit of the 
Torridon Sandstone, the striae trend about west-north-west. Further 
south, on Cul Mor, near the 1500-feet level, on the top of the escarp- 
ment of Torridon Sandstone east of Loch Skinaskink, the direction is 
a few degrees south of west. 

The general westerly movement of the ice across the mountainous 
part of Assynt, the Cromalt hills, and the Coigach district is confirmed 
by the dispersal of the boulders. Indeed, the evidence on this point is 
somewhat remarkable. For instance, on Beinn an Fhurain, which is 
composed of displaced members of the Cambrian formation, quartzites, 
fucoid beds, and serpulite grit, boulders of thrust Lewisian gneiss 
occur on the crest of the ridge, which have been borne westwards from 
the deep corries north of Ben More Assynt. The highest elevation of 
the thrust Lewisian gneiss in Corrie Mhadaidh is from 1750 to 2250 
feet, and the striae on the quartzite ridge of Beinn an Fhurain west of 
that corrie point W. 10 to 20 N. Further north, on Mullach an 
Leathaid Riabhaich, similar boulders of thrust Lewisian gneiss rest 
on the quartzite at a height of 2250 feet. On Breabag the evidence is 
no less remarkable, for on the quartzite ridge that runs southwards 
from Breabag Tarsuiim (2044 feet) about the 2000-feet level, numerous 
blocks of thrust gneiss and Moine schist have been recorded. Further 
south along the same ridge, in the direction of Meall Diamhain, on 
the outcrop of fucoid beds as well as on the quartzites, blocks of thrust 
gneiss and granulitic quartz-schist are met with. The boulders of 
thrust gneiss have been derived from the belt of this material that has 
teen traced continuously from Ben More Assynt south to Sgonnan Mor, 
while the blocks of granulitic schists have been carried westwards from 
the Moine schist area, the average height of which is lower than that 
of the Breabag ridge. It follows, therefore, that during this westerly 
movement the Moine schist erratics must have been borne to levels at 
least 500 feet higher than the sources from which they were derived. 

When we pass beyond the limit of the Ben More group of mountains 
to Cul Beag (2523 feet) a mountain of Torridon Sandstone west of the 
Cromalt hills the evidence is equally conclusive regarding the trans- 
port of materials in a westerly direction to higher levels. For there, 
at a height of 2300 feet, blocks of Moine schist rest on the Torridon 
Sandstone. Comparing the elevation of the Cromalt hills between 
Coigach and the river Oykell with the height of these erratics on Cul 
Beag, it is obvious that the latter must have been raised about 600 feet 



186 BATHYMETRICAL SURVEY OF 

in the course of the movement. On Cul Mor, north of Cul Beag, our 
colleague Mr. Hinxman found a boulder of nepheline-aegiriiie syenite 
just below the 2000-feet contour-line, which must have been derived 
from the Cnoc na Sroine and Aultnacallagach igneous mass (see 
Geological Map). No part of that mass reaches an elevation greater 
than 1306 feet, so that this boulder, during the westerly movement of 
the ice, must have been raised at least about 600 feet above its parent 
source. 

There is hardly any trace of boulder clay within the mountainous 
part of Assynt. This deposit appears in some of the valleys occupied 
by the Moine schists, as for instance, in the catchment basins of the 
Cassley and the Oykell, and in the valleys of the Cromalt hills. The 
drift deposits consist chiefly of moraines which have indeed a wide 
distribution. An examination of the moraiiiic material, and of the 
boulders on the mounds, points to a period of confluent glaciers when 
the mountainous part of Assynt, together with the Cromalt hills, 
Cul Mor, Cul Beag, and the Coigach mountains, became independent 
centres of dispersion. The feathered arrows on the geological map 
indicate this later movement, and show a marked contrast from the 
persistent westerly trend of the earlier glaciation. A glance at the 
map will show, for instance, how from the north-east slope of the 
Glas Bheinn and Ben More Assynt range the later ice spread over the 
moorland plateau east of Gorm Loch Mor and Fionn Loch Mor onwards 
in the direction of Loch Shin. This plateau is covered with moraine 
mounds which contain boulders and debris of Cambrian quartzite, 
borne from the mountains to the west on to the area occupied by the 
Moine schists. Again, in the valley of the Cassley that drains the 
great corries east of Ben More Assynt and Carn na Convaroan, boulders 
of Cambrian quartzite have been traced for about 15 miles down to 
Invercassley. Again, on the Moine schist plateau east of Loch Ailsh 
and south-east of Sgonnan Mor, moraines occur containing blocks 
of Cambrian quartzite and thrust Archaean gneiss from that area. 
Further, on the west side of Glas Bheimi and Ben More Assynt, in 
the neighbourhood of Inchnadamph, part of this confluent glacier ice 
streamed northwards up the Skiag valley, carrying boulders of the 
intrusive porphyrite of Beinn Gharbh in its train. Local ice streamed 
off the eastern slopes of Canisp and Beimi Gharbh, which coalesced with 
that radiating from Breabag. In like manner, from the eastern slopes 
of Cul Mor and Cul Beag, local glaciers diverged which united with 
that moving off the Cromalt hills, and were deflected westwards towards 
the Archaean plateau and northwards towards Strath Kanaird. 

On referring to the geological map, it will be seen that most of the 
lochs lie within the area occupied by the Archaean gneiss. As the 
region is remarkably free of drift, the lochs lie in hollows in the solid 
rock, and are therefore rock-basins. Indeed, any one who visits the 



THE FRESH- WATER LOCHS OF SCOTLAND. 187 

area cannot fail to be struck with the number and irregular outlines 
of the lakes in the plateau of Archaean gneiss. While mapping that 
region, it was obvious that the direction of many of the lochs and of 
their branches had been largely influenced by the trend of lines of 
shearing and lines of fault, by the trend of groups of intrusive dykes, 
and by the presence of ultrabasic masses, which weather more readily 
than the pyroxenic gneiss. In view of these facts, the irregular contour 
of the lakes on the Archaean plateau, as proved by the soundings, is 
what might naturally be expected. 

Loch Assynt. This is the largest and by far the most important 
lake in the Assynt district. Round the upper end and along the 
north-east shore from Inchnadamph to the southern base of Quinag, 
it is floored by Cambrian and Torridonian strata, while the remainder 
rests on the Archaean gneiss plateau. It lies along an old consequent 
valley, the origin of which dates back to a time when the surface 
configuration was very different from what it is now. Originally, the 
lake was of larger dimensions, for at its upper end it has been silted up 
by the river Loanan; indeed, in that direction it must have extended 
at one time almost to Stouechrubie. At its lower end it must formerly 
have continued down to the narrows above Inveruplan a distance of 
over two miles from the foot of the loch, where a rocky barrier of gneiss 
and intrusive dykes crosses the river Inver. From that point upwards 
to the present lower limit of the lake an alluvial terrace is traceable, 
through which the river follows a winding course. During its former 
extension, Loch Assynt must have been continuous with Loch Uidh na 
Geadaig and Loch Leitir Easaich. 

The soundings show that this rock-basin is comparatively uniform. 
The 50-feet contour-line runs from the present lower limit of the lake 
to near the mouth of the river Loanan ; the 100-feet contour-line, from 
the bend at Loch Leitir Easaich to near the schoolhouse at Inchna- 
damph a distance of 5 miles; the 150-feet contour-line is continuous 
from a point opposite Tomore to near the schoolhouse at Inchnadamph, 
thus forming one basin 4| miles long. Five basins are enclosed by 
the 200-feet contour-line, and three basins by the 250-feet line. The 
height of the surface of the lake above sea-level is 215 feet, and the 
greatest depth is 282 feet, within the Archaean area near Tobeg and 
Eilean Assynt. At that point the lake is 67 feet below sea-level. A 
glance at the bathymetrical map will show that the long axes of the 
deeper basins coincide with the trend of the loch between Loch Leitir 
Easaich and Inchnadamph, and that they lie nearer the southern shore. 
This feature is worthy of note, as it is a continuation of an important 
fault which has been traced for miles along Glen Salach in a north- 
west direction, in the line of which lie several lakes (see Geological 
Map). It must be borne in mind, however, that this line of disruption, 
which has produced brecciation of the Archaean gneiss and dykes along 



188 BATHYMETRICAL SURVEY OF 

Glen Salach, is of pre-Torridonian age, and has no connection with the 
later post-Cambrian movements. It developed a line of weakness, 
which, when stripped of the overlying Torridon Sandstone and 
Cambrian strata, would aid erosion either by the action of running 
water or land ice. Several faults enter the lake on the south side 
between Tobeg and Rudh' an Alttoir, which, trending in a north-east 
direction, are coincident with inlets at the margin. Indeed, it is not 
improbable that the sudden deflection of the lake between Loch Assynt 
Lodge and Little Assynt its course there being south-west and north- 
east may be due to faults in the same direction, entering the lake at 
Little Assynt. 

Loch Leitir Easaich. This is a shallow rock-basin on the Archaean 
plateau, which, as already indicated, was originally an arm of Loch 
Assynt. Its long axis, trending north-west, coincides in direction with 
that of the Glen Salach fault, but the deepest sounding 70 feet 
does not lie in the line of this pre-Torridonian dislocation, but in a 
small basin to the south of it. 

Loch Beannach is another shallow rock-basin on the Archaean gneiss 
with very irregular outlines, its greatest depth being 38 feet. Numerous 
rock knobs project above the surface of the water. The long arm 
trending north-west to Loch an Dubh Uidh coincides in direction with 
an epidiorite dyke and with a line of disruption, but the numerous 
small bays reflect the varying lithological characters of the Archaean 
gneiss. 

Loch Druim Suardalain and Loch na Doire Daraich are two shallow 
rock-basins lying in the consequent valley of the Glen Canisp river 
(Amhainn na Clach Airidh). A chain of small lakes lies along this 
ancient valley, all of which are rock-basins now in course of being 
silted up. The greatest depth of Loch Druim Suardalain is 31 feet. 
Several small faults cross this lake in a north-east direction, which 
produce a slight displacement of the intrusive dykes, but they do not 
seem to have modified the floor of the loch as indicated by the 
soundings. Loch na Doire Daraich is only about 9 feet deep. 

Loch Crocach and Loch an Tuirc are likewise shallow rock-basins on 
the bare Archaean floor. The long axis of the former loch, which is 
about 1^ miles in length, lies in the line of a well-marked fault which 
has been traced for miles across the Archaean plateau. There can be 
little doubt that the straight feature of the west shore is due to this 
dislocation. Numerous roches moutonnees rise above the surface of the 
lake towards the east side. Again, in the case of Loch an Tuirc, a 
fault which shifts the intrusive dykes enters the lake at its outlet, and 
crosses it in a north-easterly direction. The straight feature on the 
south side coincides with a zone of newer shearing in the Archaean 
gneiss trending east and west. 

Loch Veyatie and Fiotin Loch. These lakes lie in rock-basins in the 



THE FRESH- WATER LOCHS OF SCOTLAND. 189 

direction of an old consequent valley traversing the Archaean plateau 
and the Torridonian and Cambrian strata north-west of Elphin. These 
lakes were evidently at one time connected, for an alluvial terrace 
stretches up the valley from the Fionn Loch to near Loch Veyatie. The 
height of the surface of the Fionn Loch is 357 feet above sea-level, and 
the height of the alluvial terrace is 379 feet, so that the lake has been 
lowered by about 20 feet. The long axis of this lake coincides generally 
with the strike of the original banding of the Archaean gneiss, which 
there dips to the south-west at angles varying from 20 to 30. Several 
large intrusive dykes trend obliquely up the loch, and lines of newer 
shearing enter the lake on the north-west side, trending north-west. 
Indeed, these shear lines have evidently determined the arm of the 
lake that runs westwards beyond the point where the river Kirkaig 
drains this sheet of water. Though of irregular contour, the soundings 
show that it is a long narrow basin, the deepest sounding being 90 feet. 

In like manner, though Loch Veyatie is 4 miles long, the soundings 
show that it is a comparatively shallow basin, the deepest sounding 
being 126 feet north of Loch a' Mhiotailt and near the foot of the 
loch. The long axis of this lake is oblique to the strike of the early 
foliation of the Archaean gneiss, and several large intrusive dykes enter 
the foot of the lake, the direction of which coincides with that axis. 
The upper part of the lake is floored partly by Cambrian and partly 
by Torridonian strata, the lofty mountain of Cul Mor rising to a 
height of 2786 feet on the south side. The soundings show that there 
are three small basins, each over 100 feet in depth, two of which lie 
north-north-east of the great escarpment of Torridon Sandstone of Cul 
Mor, and the third near the foot, opposite an escarpment of Archaean 
gneiss which rises to a height of 200 feet above the level of the lake. 

Loch a' Mhiotailt is an arm of Loch Veyatie, near the foot of the 
latter, and on its south side. The deepest sounding is 69 feet. The 
long arm of the lake has evidently been determined by faults which 
shift the outcrops of the intrusive dykes. 

Loch Cam flows into Loch Veyatie at its upper end, near Elphin. 
The western portion of this lake is floored by Archaean rocks, and the 
central and eastern portions by Torridonian and Cambrian strata. 
The soundings show that it is a comparatively shallow rock-basin. 
Much of the east part near Elphin is under 50 feet in depth, and the 
deepest soundings recorded at two localities further west are 122 feet. 
One of these localities is at the narrows, where the lake is floored by 
Cambrian quartzite, and the other about two-thirds of a mile from the 
head on the Archaean plateau. The soundings further show that near 
the head of the lake on the south-west side there is a narrow basin 
trending nearly west-north-west, enclosed by the 100-feet contour-line, 
the direction of which coincides with a line of pre-Torridonian shearing 
that has been traced for miles to the west-north-west into the Fionn 



190 BATHYMETRICAL SURVEY OF 

Loch. The soundings also prove that there is a steep cliff along the 
south shore parallel to this line of shearing, which is continued west- 
north-west beyond the lake towards the Fionn Loch. 

Of all the lakes within the Archaean plateau, Loch Skinaskink 
presents the most irregular outlines. Still, it is obvious that its 
southern portion lies along a consequent valley, which rises between 
Cul Mor and Cul Beag. The lake is now drained by the river Polly, 
which, where it leaves the loch, flows over a barrier of Archaean gneiss. 
The longer axis of the loch south-west of Eilean Mor coincides with the 
trend of the early foliation of the gneiss and of certain intrusive dykes. 
The north-west margin of the loch has been determined by a pre- 
Torridonian line of fault, which shifts the outcrops of the intrusive 
dykes. 

Numerous rocky islets rise above the level of the loch, which, 
together with the soundings, reflect the varying character of the 
Archaean gneiss and intrusive dykes. Various faults enter the loch, 
which in many cases have given rise to well-marked inlets. The deepest 
sounding is 216 feet, which occurs not far to the south of Eilean Mor, 
in the line of the longest axis from south-east to north-west, and 
where that axis is intersected by a north-east and south-west fault. 

Loch Lurgain lies wholly within the Torridon Sandstone area, and 
is a true rock-basin, for at its outlet it flows over a barrier of rock into 
Loch Bada na h-Achlaise. The trend of the upper part obliquely 
crosses the strike of the Torridon Sandstone, while that of the lower 
is more or less parallel to it. About midway down the loch, roches 
moutonnees appear, and the soundings there vary from 20 to 56 feet. 
Above these islands there is a simple basin, the deepest sounding being 
156 feet north-east of Beinn Eun. Below the islands the basin is 
comparatively simple, the greatest depth being 148 feet. At the foot 
of the loch, immediately in front of the rocky barrier, the basin 
enclosed by the 100-feet contour-line is broader than further up the 
lake. 

Loch Bad a' Ghaill is a true rock-basin, which, save at its lower 
end, where the rocky barrier is composed of Archaean gneiss, is floored 
by Torridon Sandstone. The soundings show that this lake forms two 
well-marked basins. The greatest depth of the upper one is 180 feet, 
which is a few feet below sea-level, and the deepest sounding of the 
lower basin is 153 feet. The ice-movement, as indicated by the striae, 
seems to have coincided generally with the direction of this lake and 
Loch Lurgain. Morainic drift is met with at intervals along the shores 
of these lakes. 

Loch Owskeich is likewise a rock-basin, the barrier being formed of 
Torridon Sandstone. The loch, save at its upper end, where there 
is a ridge of Archaean gneiss, is floored by Torridon Sandstone. The 
soundings show that this lake has been modified by a powerful north- 



THE FRESH- WATER LOCHS OF SCOTLAND. 191 

north-east and south-south-west fault skirting the eastern shore, 
whereby the Torridon Sandstone has been thrown down against the 
Archaean floor on the east side. A glance at the map will show how 
the contour-lines run parallel to that fault and close to the shore, 
and that the deepest sounding, 153 feet, is not far from the line of this 
dislocation. 

Loch Urigill and Loch Maol a' Choire are shallow rock-basins in the 
Cambrian limestone, the erosion of which may be partly due to 
solution. 

Loch Borralan lies along the line of a consequent valley, near the 
headwaters of the river Kirkaig, and probably not far from the 
original axis of uplift in early Palaeozoic times. It is a shallow rock- 
basin, floored by igneous rocks which belong to the igneous mass of 
Cnoc na Sroine, with some drift along its margin. 

From the evidence now adduced, it is obvious that the plateau of 
Archaean gneiss with its intrusive dykes is dotted over with lakes of 
various sizes, which, with the exception of the lower part of Loch 
Assynt, are of moderate depth. Indeed, most of them are shallow 
basins, which reflect the varying types of gneiss and intrusive dykes 
and their subsequent deformation. It is, no doubt, true that the 
numerous shear-lines and faults of pre-Torridonian age that traverse 
the Archaean plateau have determined to some extent the features of 
these lakes; but we are, nevertheless, of opinion that the evidence 
taken as a whole is in favour of the theory that they have been mainly 
produced by the erosive action of ice. 



NOTES ON THE BIOLOGY OF THE LOCHS IN THE ASSYNT DISTRICT. 
By JAMES MURRAY. 

Only an incomplete sketch can be given of the biology of this 
district, as collections of plankton were made in only twelve out of the 
twenty lochs surveyed. Loch Assynt is the largest loch in the district, 
but four others, viz., Lochs Lurgain, Skinaskink, Bad a' Ghaill, and 
Owskeich, are moderately large and of considerable mean depth, so 
that they fall to be classed rather with the large lochs than with 
the small ones. The remainder are small or of low mean depth. 

The fauna of the plankton was very uniform throughout these lochs, 
differing chiefly in the presence in some of them of one or other of the 
northern species of Diaptomus, D. Wierzejskii, I), laciniatus, in the 
Daphnia being D. lacustris in some and D. galeata in others, and in 
the greater abundance of Rotifera and Rhizopods in the shallower 
lochs. Though the three common Scottish species of Diaptomus were 



192 BATYHMETRICAL SURVEY OF 

found in the district, they were never all found together in one loch, 
as was commonly the case elsewhere in Sutherland. The Daphnia in 
most of the lochs was the typical D. lacustris. In one loch this was 
associated with D. galeata, while in three lochs D, galeata was alone 
observed. Leptodora was only observed in Loch Skinaskink, and 
Bythotrephes was not observed at all. 

While the fauna thus offers little that is remarkable, the flora, on 
the other hand, is notable for the great wealth of Algae, especially of 
Desmids. Over fifty species of Desmids were observed, and between 
thirty and forty of these sometimes occurred in one loch. Messrs. 
West, commentii^g on the Desmid flora of this part of Scotland, state 
that the plankton is unique in the abundance of its Desmids, and that 
the most conspicuous of these are of a distinctly western type, being 
found in Europe only along the extreme north-western coasts, while 
in North America they are eastern species. The southern and eastern 
limits of this remarkably rich area in Scotland cannot yet be fixed; 
in Sutherland it extends right across Scotland. An examination of 
many hill lochs in Perthshire and in the south of Scotland showed no 
such rich flora there. When the distribution of the Desmid flora is 
worked out, it will be of interest to observe whether the area covered 
by those western species coincides with that occupied by the northern 
Calanidae, Diaptomus Wierzejskii and D. lacintatus, which are so 
generally distributed in Sutherland, though they also occur in many 
spots further south. 

Loch Assynt. The plankton of this loch closely resembles that of 
the larger lochs in the south, only the typically pelagic Entomostraca 
and Rotifera being present. It is noticeable that neither Diaptomus 
Wierzejskii, D. laciniatus, nor Daphnia galeata, species widely dis- 
tributed in the district and also occurring in many of the large lochs 
further south, was observed here. The loch further resembles many 
other large lochs in the presence of numerous skeletons of Clathrulina 
elegans. The only Rotifer calling for mention is Triarthra longiseta, 
a species not usual in large lakes. Unlike the other lochs of the 
district, there were very few Desmids in the plankton. The quantity 
of plankton was very small. 

Loch Lurgain. The fauna comprised only the usual pelagic species, 
among which Cyclops strenuus was most abundant. The Daphnia was 
D. galeata. Diaphanosoma brachyurum was present in some numbers. 
The flora was remarkable for the number of Desmids, especially of the 
genus Staurastrum, including the beautiful large species, S. longis- 
pinum and S. arctiscon. 

Loch Bad a' Ghaill. The somewhat meagre plankton was almost 
exactly of the type found in deep lochs, differing only in the greater 
abundance of Rotifera, among which were Plcesoma, Gastropus, and 
Triarthra. The commonest animal was Cyclops strenuus. About a 



THE FRESH- WATER LOCHS OF SCOTLAND. 193 

dozen species of Desmids were observed, including Staurastrum longis- 
pinum and S. gracile, var. bulbosum. 

Loch Owskeich. The fauna was much richer than that of Loch 
Bad a' Ghaill, with which, from position and size, it is best comparable. 
Diaptomu* yracilis and D. laciniatus were both present. The Daphnia 
was D. galeata. There were many filamentous Algae and Desmids, 
among which occurred Staurastrum Brazil iense. 

Loch Skinaskink. The plankton was very rich, and, notwithstanding 
the large size and considerable mean depth of the loch, resembled that 
of a shallow loch in the great numbers of Rotifers, Desmids, and 
Protozoa. There were two species of Diaptomus, D. gracilis and D. 
laciniatus, and two of Daphnia, D. lacustris and D. galeata. Among 
the Rotifera were two species which, though pelagic, are not usual in 
large lakes, viz., a Synchceta and a Plcesoma. The Desmids included 
Staurastrum Brazil ie?ise and S. ophiura. 

Loch Fionn. This loch, though long, is so narrow as to be little 
more than an expansion of the river. When in spate, as on the occasion 
of the visit of the Lake Survey, there is a decided current down the 
loch. As would be expected in the circumstances, life was very scarce 
and of few species. Two forms of Bosmina were present, B. obtusirostris 
and its variety B. longispina. 

Loch an Tuirc. Entomostraca were numerous, but of few species. 
Rotifera were scarce. Filamentous Algae were abundant, but there 
were few Desmids. 

Loch Beannach. Organisms were not very abundant. Only the 
commonest pelagic Entomostraca were present. Rotifera were more 
numerous, including, in addition to the usual pelagic species, Gastropus 
stylifer and a species of Plcesoma. 

Loch na Doire Daraich. The very abundant fauna of this loch 
closely resembled that of the adjacent Loch Druim Suardalain, the 
most notable difference being the more numerous Rotifera. Among 
these were Floscularia pelagica, Triarthra longiseta, Pterodina patina, 
Copeus cerberus, Dinocharis Collinsii. Among the numerous Desmids 
were Micrasterias furcata, M. j)innatafjda, Staurastrum grande, and 
S. longispinum. 

Loch, Druim Suardalain. This shallow loch had the richest fauna 
found in the lochs of the district. The flora was also very rich. About 
a dozen species of Rotifera were seen, including Callidina Brycei. 
Over thirty species of Desmids occurred, among which were Staurastrum 
grandr, S. ophiura, and S. serangulare. There was nothing among 
the Entomostraca calling for remark, only the commoner pelagic and 
shallow-water species being observed. 

Loch Maol a' Choire. Crustacea were very abundant, including a 
species of Gammarus. Diaptonnis Wierzejskii was the only Calanid 
observed. It was in a collection from this loch that the species was 

o 



194 BATHYMETRICAL SURVEY OF 

discovered in Britain by Dr. Scott. The usual pelagic Rotifera were 
present. No Desmids were seen. 

Loch Awe. The most abundant organism was a variety of Diaptomus 
Wierzejskii. Sida was seen here, and in no other lake in the district, 
being somewhat late in the season for this species. Very few Rotifera 
or Algae were noticed. 



THE FRESH-WATER LOCHS OF SCOTLAND. 195 



LOCHS OF THE MORAR, BASIN. 

THREE lochs lying in the basin of the river Morar were surveyed 
viz., Loch Morar, Loch Beoraid, and Loch an Nostarie. There are 
a number of other small lochs in this catchment-basin, but as there 
were no boats on them they could not be surveyed. Loch Morar is the 
principal loch in the basin, and it gives great interest to the whole 
area from the fact that it is not only the deepest lake in Scotland, but 
in the British Islands ; indeed, the bottom of this loch forms the deepest 
hole in the continental plateau on which our islands are situated. 

From the accompanying sketch-map (Fig. 32), it will be seen that 
Lochs Morar and Beoraid are parallel to each other, and run in an east- 
and-west direction. The overflow from Loch Beoraid, which lies about 
3 miles to the south of Loch Morar, enters Loch Morar about its centre 
by the river Meoble, while the overflow from Loch an Nostarie, which 
lies to the north, enters Loch Morar at its western end by the river 
Loin. 

The west end of Loch Morar is only about 500 or 600 yards from 
the sea, and its outflow is by the river Morar, which in its course falls 
over a rocky barrier, at the foot of which is a famous salmon pool. 

The total drainage area of the Morar basin is calculated at 42,000 
acres, or over 65J square miles. The whole region is rocky and 
mountainous. The district has not yet been mapped by the Geological 
Survey, but it is believed that the whole basin lies entirely in the 
crystalline schists of the Moine series of the Geological Survey, the 
main strike being north-north-east to south -south-west. The rocks 
seen at the barrier at the mouth of the loch are composed of hard 
quartzose flagstones or siliceous Moine schists. The direction of the 
hills at the belt which separates Loch Morar from the sea agrees 
generally with the strike of the rocks. Lochs Morar and Beoraid 
occupy true rock-basins, but it seems almost certain that the outlet 
of Loch Morar was at one time to the south-west, because the col 
there does not rise more than 100 feet above the sea, and there is a 
narrow belt of comparatively flat ground running southwards towards 
the source of the burn called Allt Cam Carach. It will be observed, 



196 



BATHYMETRICAL SURVEY OF 



by an examination of the depth map, that the deep water at the west 
end of the loch runs in the direction of this flat ground. Some deep 
borings along this flat ground might lead to interesting results. 

Loch Morar (as well as Loch Beoraid) is a glen-lake which lies in a 
transverse valley that is to say, in a valley the direction of which 
is independent of the geological structure of the region and crosses 




English Miles 
PIG. 32. INDEX MAP OF THE MORAR, SHIEL, AILORT, AND NAN UAMH BASINS. 



irregularly the strike of the rocks. This fact very probably accounts 
for the steep sides and the great depth to which the valley has been 
scooped out. Should the country be depressed about 40 feet, Loch 
Morar would be converted into a submerged valley and an arm of the 
sea like Loch Etive. By some observers it is held that the great depth 
of Loch Morar precludes the idea that it was scooped out by river- 
action or by ice. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



197 



Loch Morar (see Plate XLIIL). This is a large and beautiful loch, 
lying amid wild and magnificent scenery on the west coast of Inverness- 
shire, in the south-west portion of that county, immediately to the 
south of Loch Nevis, which is a sea-loch running inland for 12 miles 
from the Sound of Sleat. The west end of Loch Morar is about 3 
miles from Arisaig, and 2J miles from Mallaig. Morar station, on 
the Mallaig branch of the West Highland Railway, is within a few 
hundred yards of the west end. 

The loch is a little over 11J miles in length, and the maximum 
breadth is over H miles near the west end; the mean breadth is 




FIG. 33. LOCH MOEAR, LOOKING EAST FKOM THE WEST END. 

(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.S.E.) 

nearly T %- of a mile, or about 7^ per cent, of the length. The area 
covered by the lake is 6596 acres, or nearly 10J square miles. 

There are several islands, more or less richly covered with vegetation, 
at the west end of the loch (see Fig. 33), and parts of the surrounding 
land, especially on the north side, are fairly well wooded, all of which 
greatly adds to the beauty and picturesqueness of the scenery at this 
part, but as one proceeds eastwards towards the head of the loch the 
scenery becomes wilder, the vegetation more scanty, and the mountains 
on both sides of the loch rise higher and more steeply. At many 
places on the north shore they rise precipitously from the water's edge, 
and around the head of the loch they reach a height of fully 3000 feet. 



198 BATHYMETRICAL SURVEY OF 

Loch Morar is fed by numerous small burns and streams, the largest 
feeder being the Meoble river, which, issuing from Loch Beoraid, falls 
in, after a course of about 3 miles, at " Camas Luinge," a bay on the 
south shore. 

On the north shore, about 4J miles from the head of the loch, is a 
large bay called " South Tarbet Bay," and here a narrow neck of land 
about half a mile wide separates Loch Nevis from Loch Morar. A 
track which runs up the north shore of Loch Morar to Tarbet on Loch 
Nevis, crosses this neck of land by a narrow pass which rises to a height 
of 200 feet. For a distance of about 6 miles from the west end, the 
loch gradually narrows until a breadth of two-thirds of a mile is attained 
a little to the east of Brinacory island on the north shore, then it 
expands again to a breadth of over a mile opposite the entrance of the 
Meoble river; gradually it narrows again until at its eastern end the 
breadth is about one-third of a mile. 

For a long time Loch Ness bore the reputation of being the deepest 
loch in Scotland, but in the year 1879 Mr. J. Y. Buchanan, F.K.S., 
showed that Loch Morar contained depths of over 1000 feet, which 
was deeper by several hundred feet than Loch Ness. In April, 1887, 
Sir John Murray took a series of 18 soundings down the centre of the 
loch, the greatest depth recorded being 1050 feet. In September of 
the same year he again took 12 soundings at the deepest part of 
the loch, the greatest depth obtained being 1026 feet. All these 
soundings were taken by means of hempen-rope sounding-lines, as 
well as those taken in 1892 by Dr. Thomas Scott, who recorded a 
depth of 1020 feet. In June, 1896, Sir John Murray and the late Mr. 
Fred. P. Pullar made a bathy metrical survey of the whole loch with 
a wire-rope machine, but the chart they prepared was not published, 
as it was found that the machine employed was untrustworthy. It was 
therefore resolved to make a completely new survey. This was carried 
out in June and July, 1902. Since that date the loch has been 
frequently visited by members of the Lake Survey staff for the purpose 
of taking temperatures and making biological observations. 

The surface of the loch at the time the survey was made, in June, 
1902, was 30-5 feet above sea-level, and in March, 1903, the level was 
found to be 35 feet above the sea a difference in level of 4J feet. 
Altogether 1100 soundings were taken in the loch, or about 100 
soundings to the square mile; the maximum depth recorded was 1017 
feet. This is less than previous results, but is to be accounted for by 
the use of wire rope, which nearly always gives a lesser depth than 
the soundings with ordinary sounding-lines. The general results are 
set forth on the accompanying map of the loch, with various cross- 
sections. 

Loch Morar is of simple conformation, the bottom falling on all sides 
down to the deepest part, but with here and there a few minor undula- 



THE FRESH-WATER LOCHS OF SCOTLAND. 199 

tions of the lake-floor, especially in the wider western half of the loch, 
where the contour-lines of depth are much more sinuous in character 
than in the narrower eastern half. This is most noticeable in the 
vicinity of the islands at the west end; the line of soundings running 
south from Rudha Port na Coite shows several irregularities of the 
lake-floor, and causes the 300-feet and 500-feet contours to twist in a 
peculiar manner. Proceeding eastwards, the bottom undulates in such 
a way as to cut up the 700-feet basin into three portions separated from 
each other by shallower water, and towards the north shore, opposite 
Camas na Togalach, a sounding of 367 feet is recorded separated from 
the main basin by a shoaling of the bottom covered by 229 feet of water. 
Farther east again, opposite Roinn a' Ghiubhais, the bottom shoals 




PIG. 34. DIAGRAMMATIC SECTION ACROSS LOCH MORAR AND THE HILLS ON BOTH 
SIDES, SHOWING RELATION OP DEPTH TO HEIGHT. NATURAL SCALE. 



slightly, so as to isolate a small area exceeding 900 feet in depth from 
the main 900-feet basin. Opposite the entrance of the river Meoble, on 
the southern shore, a sounding of 97 feet was recorded comparatively 
near shore, which gives rise to a prolongation of the 100-feet contour- 
line in that direction. Towards the east end of the loch, opposite Sron 
an Drutain on the north shore, a rise of the bottom was observed 
covered by 74 feet of water, surrounded by depths exceeding 100 feet. 

The deepest part of the loch is at the wide portion opposite the 
mouth of the Meoble river ; here, in the centre of the loch, the maximum 
depth of 1017 feet was obtained, at a spot nearly midway between the 
two ends of the loch. The area over 1000 feet in depth is not large, 
extending only to a little over 4 acres. One sounding of 1002 feet was 
obtained about 400 yards to the north-east of this area. 

The area enclosed by the 900-feet contour extends to a length of 
a little over 2 miles, with a maximum breadth of a quarter of a mile, 
situated about 5J miles from the west end of the loch and 4 miles from 
the east end. A small detached area over 900 feet in depth, with a 
length of half a mile, lies about two-thirds of a mile to the west of 
the main 900-feet basin. 

The 800-feet contour encloses an area 4 miles in length with a 
maximum breadth of about one-third of a mile. It extends from 4 
miles from the west end of the loch to within 3 miles of the east end. 



200 



BATHYMETRICAL SURVEY OF 



There are three depressions over 700 feet in depth. The main one 
is nearly 5 miles in length, with a maximum breadth of two-fifths of a 
mile, extending from nearly 4 miles from the west end of the loch to 
within 2J miles of the east end. The other two depressions are small; 
one lies about half a mile to the west of the main depression, and is 
three-quarters of a mile in length; close to its western extremity lies 
the third depression, which has a length of about one-third of a mile. 

The 600-feet contour encloses an area which is 1\ miles in length, 
extending from about 2 miles from the west end of the loch to 2 miles 
from the east end. 




FIG. 35. LOCH MORAR, LOOKING TOWARDS THE DEEPEST PART. 

(Photograph by Mr. J. A. Harvie-Bmcn, F.Z.S.) 



The 500-feet contour encloses an area extending to over 7^ miles in 
length, reaching from If miles from the west end of the loch to about 
2 miles from the east end. 

The 400-feet contour encloses an area over 8| miles in length, 
extending from 1J miles from the west end to 1 mile from the east end 
of the loch. 

The area over 300 feet in depth is 9J miles in length, extending 
from nearly 1J miles from the west end to a little over half a mile from 
the east end of the loch. There is a small detached area of over 300 
feet in depth, about 5 acres in extent, near the north shore, a quarter 
of a mile to the west of Brinacory island. 



THE FRESH-WATER LOCHS OF SCOTLAND. 201 

The area enclosed by the 200-feet contour is nearly 10J miles in 
length, extending from about a mile from the west end to about one- 
sixth of a mile from the east end of the loch. 

The area enclosed by the 100-feet contour is over 11 miles in length, 
extending from one-fifth of a mile from the west end of the loch to a 
short distance from the east end. 

The area covered by less than 100 feet of water is 2784 acres. The 
areas between the consecutive contour-lines and the percentages to the 
total area of the loch are as follows : 

to 100 feet 2784 acres 42 -2 per cent. 

100,, 200 863 13-1 

200,, 300 528 8'0 

300,, 400 488 7'4 

400,, 500 331 5-0 

500 600 331 5-0 

600,, 700 547 8 -3 

700,, 800 ,, 111 1-7 

800,, 900 ,, 530 8-0 

900 ,, 1000 ,, 79 1-2 

Over 1000 , 4 , O'l 



6596 ,, 100-0 



These contour-lines of depth approach each other very closely in 
many places, showing that the slopes are very steep at these points. A 
little to the west of the promontory called " Rudha nam Faiseachean ' ' 
on the south shore, south-east of the islands, this is very marked, the 
slope being as much as 1 in 2J. Farther east on the south shore, off 
"Eilean Allmhara," the slope is again very steep, as it also is off 
Brinacory island, which lies almost opposite on the north shore. 

As the surface of the loch is only 30 feet above sea-level, almost 
the entire bed of the loch is below the level of the sea. The area 
draining directly into Loch Morar is over 33,800 acres, or about 52 
square miles. 

The volume of water contained in the loch is estimated at 
81,486,000,000 cubic feet, and the mean depth at 284 feet. Although 
Loch Morar is the deepest loch, Loch Ness has a volume three times 
as great, and its mean depth is 436 feet. 

The deepest Scottish lochs next to Loch Morar are 

Loch Ness .. ... ... ... ... ... 751 feet. 

,, Lomond .. 623 ,, 

,. Lochy '... 531 

,, Ericht 512 

Tay 508 ,, 

In the sea to the west of Morar there is no depth approaching 1000 
feet, with the exception of a deep spot of 834 feet (139 fathoms) between 



202 



BATHYMETRICAL SURVEY OF 



the islands of Rum and Skye, so that to get a depth of 1000 feet one 
must go west of St. Kilda and Ireland, beyond the 100-fathoms line 
in the Atlantic ocean. There are no depths comparable to this in the 
North Sea, but the submarine valley known as the "Norwegian Gut," 
which runs round the west and south coast of Norway, is remarkably 
deep, depths of 1794 feet (299 fathoms) and 1710 feet (285 fathoms) 
having been obtained at the part called "The Sleeve." 

There are seven lakes on the continent of Europe which exceed 
Loch Morar in maximum depth, and in the following table their 
maximum depths, heights of the water surface above sea-level, and 
depths of their floors below sea-level, are shown as compared with 
Loch Morar. The first four of these lakes are in Norway, the other 
three are well-known Italian lakes.* 



Name. 


Max. depth. 


Height above 
sea-level. 


Depth below 
sea-level. 


Hornisdalsvand 


F.et. 
1594-5 


Feet. 

167-3 


F.et. 

14272 


Mjosen 


1482-9 


396-9 


1086-0 


Salsvatn. . 


1460-0 


42-6 


1417-4 


Tinnsjo 


1437-0 


606-9 


830-1 


Como 


1341 -8 


652-9 


688-9 


Maggiore 


1220-4 


472-4 


748-0 


Garda 


1135-1 


213-2 


921 -9 


Morar 


1017'< 


30%") 


986-5 


' 









The Lake of Geneva, in which very important and comprehensive 
limnological work has been done by Prof. Forel, Dr. Ed. Sarasin, and 
others, has a maximum depth of 1013-8 feet, and the height of the 
water surface is 1220-4 feet above sea-level; the deepest part of the 
lake-floor does not, therefore, go below sea-level, but lies at 206-6 feet 
above it. 

Temperature Observations. A large number of observations on the 
temperature of the water of Loch Morar has been made in various 
seasons and in different years. On April 29 and September 3, 1887, Sir 
John Murray took several series of temperatures, ranging from the 
surface to the bottom. In the April observations the temperature 
varied from 43'9 at the surface to 42-0 at the bottom, a range of 
1 0< 9, and in September the variation was from 57-8 at the surface to 
42-l at the bottom, a range of 15-7. On July 2 and 3, 1902, serial 
temperatures were taken by the Lake Survey, and the variation was 
from 55-2 at the surface to 42-2 at the bottom, a range of 13-0. 
Subsequently, on March 28, 1903, the temperature was found to be 



* The figures referring to these continental lakes are derived from " Halbfass, Die 
Morphoraetrie der Europaischen Seen," Zeltschr. Gesellsch. Erdk. Berlin, Jahrg. 1903, 
p. 592; 1904, p. 204. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



203 



practically uniform from the surface to the bottom at a depth of 1010 
feet, the surface temperature being 41-9, while that at the bottom was 
41'8, a range of only 0'l, and on October 23 of the same year the varia- 
tion was from 50 0> 2 at the surface to 43-0 at the bottom in 1000 feet, a 
range of 7-2. The temperature at the depth of 1000 feet has generally 
been regarded as fairly constant at about 42-0 all the year round, with 
a variation of about 0- 2, and this higher record of 43'0 may be due to 
the increased amount of water draining into the loch during the wet 
summer of 1903. The highest surface temperature recorded was one 




FIG. 36. FALLS OF MORAR. 

(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.S.E.) 



of 59-2 on June 30, 1902, off Bracora, the air temperature at the time 
being 62-8, with a moderate westerly breeze. This gives a total range 
of 17-4 between the highest surface and the lowest bottom temperature 
recorded. 

Deposits. The deposits covering the floor of Loch Morar are mostly 
dark brown in colour, which becomes almost black in the deeper parts. 
A sample from 1000 feet was dark brown when wet, and greyish-black 
when dry, containing about 50 per cent, of black vegetable matter, 
about 10 per cent, of mineral particles (quartz, mica, hornblende, &c.), 
with a mean diameter of 0-15 millimetre, and about 40 per cent, of 
amorphous clayey matter, with many fine Diatoms and a few fragments 



204 



BATHYMETRICAL SURVEY OF 



ic 



*ri-3 ? 



C~ . .9 . "P . 

* : : co o : i> 

1C 1C 1C ^ 



7^9 . .P . 9 



t^ S 
- 






O O CO 00 



CO CO O 1 r ^ CO CC 



9 ... .9 . 

CO I t ! I I ^^ C 



'5 : ^ 



ll 



s 

ce eo 



'3 



'2? 



o 

- -s d 

II I 



. -4-3 



THE FRESH-WATER LOCHS OF SCOTLAND. 

P . .9 . .9 . .9 . 



205 






00 



X QC 00 



-M 'N ^ 



cc 't- cc cc it cc 



'N : 'N ii ii 



.9 






- - 51 -i 5i v. a 5 



206 BATHYMETRICAL SURVEY OF 

of arenaceous Foraminifera. The mica is present in extremely minute 
flakes, and imperceptible to the naked eye in the unwashed material. 
In this respect the material from Loch Morar differs from that obtained 
in most of the other lochs, in the samples from which the glistening 
mica flakes attract one's attention. 

Loch Beoraid (see Plate XLIV.). Loch Beoraid is a long narrow 
loch, lying amidst wild and rocky scenery about 3 miles to the south of 
Loch Morar. There were no Ordnance Survey bench-marks available 
in the vicinity of the loch from which the level of the water surface 
could be ascertained, but, from the position of the spot-levels, the height 
was estimated at 168 feet above the sea. The loch trends in an east-to- 
west direction, and is fed by numerous small burns, the largest, Allt a 
Ghlinne Dhuinii, flowing in at the east end. The Meoble river, which 
drains the loch, issues at the west end, and, after a course of 3 miles, 
falls into Loch Morar. There are one or two small islands at the east 
end of the loch, and one large one lying in the centre, almost equidistant 
from both ends of the loch. The length of Loch Beoraid is 3J miles, and 
its maximum breadth about one-third of a mile ; the mean breadth is 
one-sixth of a mile, and the area covered by water is 352 acres, or over 
half a square mile. The number of soundings taken was 120, the 
maximum depth obtained being 159 feet; the mean depth is over 72 
feet. The volume of water is estimated at 1,156,000,000 cubic feet, 
and the drainage area extends to 7680 acres, or nearly 12 square miles. 

There are two basins over 100 feet in depth ; one at the west end of 
the loch three-quarters of a mile in length, with a maximum breadth of 
one-sixth of a mile, approaching to within one-eighth of a mile from that 
end. The maximum depth obtained in it was 147 feet, comparatively 
very near the outflow. The eastern basin is nearly 1J miles in length, 
with a maximum depth of 159 feet, the area over 150 feet in depth being 
almost half a mile in length. The 50-feet area is continuous from end 
to end, passing to the south of the large central island, the depth in the 
channel being 53 feet. Loch Beoraid is a rock basin divided into two 
separate basins by a rocky ridge which crosses the loch at the large 
island. At the west end of the loch there is a rocky barrier, and the 
river Meoble in its course forms a waterfall over rocks a short distance 
from its exit. The loch was surveyed on July 1, 1902. 

Temperature Observations. The following series of temperatures 
was taken about a quarter of a mile from the west end of the loch : 

Surface 60'0 Fahr. 

10 feet 59-8 ,, 

25 ,, 53'9 ,, 

50 51-0 

100 , 47'5 ,, 

140 , 48 -0 



THE FRESH- WATER LOCHS OF SCOTLAND. 207 

These temperatures show a range of 12*5 from the surface to 100 
feet, with a small inversion of half a degree between 100 and 140 feet. 
About 3 p.m. the surface temperature in the centre of the loch, half 
a mile from the east end, with a strong westerly breeze blowing, was 
found to be 61-4. 

Loch an Xostarie (see Plate XLV.). Loch an Nostarie is a small 
loch lying about a mile to the north of the west end of Loch Morar, 
into which it drains through the little Loch a' Bhada Dharaich and 
the Allt an Loin. It was surveyed on July 16, 1902, when, by 
levelling from an Ordnance Survey bench-mark, the level of the water 
surface was found to be 89-3 feet above sea-level. The loch has a length 
of a little over half a mile, with a maximum breadth of nearly half a 
mile, the mean breadth being a quarter of a mile. The area covered 
by water extends to 90 acres, or nearly one-seventh of a square mile. 
The number of soundings taken was 62, the maximum depth being 35 
feet, while the mean depth is very nearly 11 feet. The volume of water 
contained in the loch is estimated at 44,000,000 cubic feet, and the 
drainage area extends to 1152 acres, or If square miles. The loch is 
quite simple in conformation, the deep water occupying a central 
position. 

Temperature Observations. On the date of the survey the tem- 
perature of the water was found to be almost uniform from surface 
to bottom, the difference between the surface temperature and that at 
30 feet being only 0> 1 Fahr., as shown by the following series taken at 
4 p.m. in the deepest part of the loch : 

Surface 59 '3 Fahr. 

10 feet 59-3 

20 59-2 ,, 

30 59-2 

The details regarding the lochs in the Morar basin are given in the 
table on p. 208. 



NOTES ON THE BIOLOGY OF LOCH MORAR. 
By JAMES MURRAY. 

Salmon, sea-trout, and loch-trout abound in Loch Morar, and the 
sport is frequently very good, but the salmon as a rule are " dour " 
to rise. Charr and the powan, or fresh-water herring (Cor eg onus), are 
said to inhabit the loch. 

The biology of Loch Morar offers several peculiarities as compared 
with most of the other large Scottish lochs. The quantity of plankton 



208 



BATHYMETRICAL SURVEY OF 



i 


Ratio to 
area of 
loch. 


IT"* *^ 00 

eo >p ^* 

50 ^ 32 


i 


eS 


!s 


ec 10 o; 


s 


P 




8. 3 " 


% 


8^2* 


O 'C "* 
C -H 


o> 


JM|i 





? 


in 


S i ^ 


i 


in 


~ -^ 


5<f 


" = s 


oc 


30 


h 


1 


t^ o o 

~ l^ t^ 

-M ^1 ^1 


o 


j 


S '-' 3 




III 


1 1 1 


i 


II 


c^ S 

4t< i 5 

QO 1 '-^ 






-^ 






d^ 3 


^ J? I? 




S-8 


o 




Ifijj 


CO O O 
ip 1^ CD 







X ^ >S 


a 


1 


SI 


i 


BQ 


a 


^00 


1,1 
3 a 


^H CC O 


lb|i 


3 i si 


1 


m ~ 






il , 


p p cc 




i * 


cc to x 




! 


T3 -^ 






| 'g J 






o S o 






S PQ ^ 





THE FRESH- WATER LOCHS OF SCOTLAND. 209 

is small, the larger Entomostraca especially being deficient. With this 
is correlated an unusual clearness of the water (a white disc was visible 
in June at a depth of 42 feet). The plankton hardly varies throughout 
the year, except that Leptodora, Bythotrephes, Holopedium, and a few 
other genera appear in the summer months only. The quantity was 
slightly greater in March than at other seasons. At no season has 
Daphnia been observed in the loch, and its absence has also been noted 
by Dr. Thomas Scott (as long ago as 1892) and by Mr. D. J. Scourfield. 
This is the more remarkable as Daphnia abounds in Loch an Nostarie, 
about a mile distant, and discharging into Loch Morar by a con- 
siderable stream. The only Diaptomus was the common D. gracilis ; 
while many of the other large lochs in about the same latitude have also 
one or other of that group of closely related species represented in 
Loch Ness by D. laticeps. The Bosmina was the typical B. longispina y 
and not B. obtusirostris, which is the common species in the majority 
of the Scottish lochs. In contradistinction to the scarcity of larger 
organisms, many very small species were abundant. Desmids especially, 
of a few species, were unusually numerous in the plankton at all seasons. 
A remarkable variety of Xanthidium subhastiferum has been described 
by Messrs. West from material collected by the Lake Survey. In this 
the two spines of each side of the semi-cell, instead of lying in the same 
plane as the semi-cell, are placed side by side on the external angles of 
the wedge-shaped semi-cell. 

The aquatic plants, growing in the shallow water among the islands, 
yielded an abundant fauna of microscopic animals, especially of Rotifera 
and Tardigrada. From among these there have been described two 
new species of Bdelloid Rotifers. A new water-bear of the genus 
Echiniscus has also been described. It is distinguished chiefly by having 
the dorsal plates covered by a large hexagonal reticulation in addition 
to the usual dots. This species was very numerous in October, and has 
not yet been met with elsewhere. 



210 BATHYMETRICAL SURVEY OF 



LOCHS OF THE EWE BASIN. 

THIRTEEN lochs draining into Loch Ewe were visited by the Lake 
Survey, viz., Loch Maree, Lochan Fada, Lochs Garbhaig, Coulin, 
Glair, Tollie, Kernsary, Ghiuragarstidh, Mhic' Ille Riabhaich, a' 
Bhaid-Luachraich, Sguod, an t-Slagain, and an Drainc. The two 
last-mentioned lochs fall into the sea just outside the entrance to Loch 
Ewe, but it has been found convenient to include them with the lochs 
of the Ewe basin. The relations between the various lochs will be 
readily grasped by reference to the small index map of the district 
shown in Fig. 37. The drainage area under consideration extends 
from the mouth of Loch Ewe to the summit of Cam Odhar in the 
south, and close to the shores of Loch Fannich in the east, and is about 
30 miles in length from north to south, and about 17 miles in maximum 
width from east to west. The total area is about 220 square miles 
(excluding Loch Ewe), and, as will be seen from the table at the end 
of this paper, about 185J square miles drain into the lochs now to be 
dealt with, leaving about 35 square miles draining into the sea irrespec- 
tive of these lochs. The head- waters of the basin on the south take 
their rise on the flanks of Beinn Liath Mhor and Carn Breac, flowing 
by the river Coulin into Loch Coulin, thence into Loch Clair, thence 
by the Allt Ghairbhe into the Kinlochewe river, at Kinlochewe, which 
falls into Loch Maree at its head. A short distance along the north- 
eastern shore Loch Maree receives the outflow from Lochan Fada by 
the Abhuinn an Fhasaigh, and, still further down, the outflow from 
Loch Garbhaig* by the Amhainn na Fuirneis. At its foot Loch Maree 
receives the outflow from Loch Tollie on the west, and from Lochs 
Ghiuragarstidh and Kernsary on the north-east, and its waters are 
carried by the river Ewe into the head of Loch Ewe. The outflow 
from Loch Sguod falls into Loch Ewe on its western shore, and the 
outflow from Lochs Mhic' Ille Riabhaich and a' Bhaid-Luachraich 
on its eastern shore. Loch an t-Slagain flows into Slaggan bay at the 
entrance to Loch Ewe, and Loch an Drainc flows into The Minch a 
short distance to the west of the entrance to Loch Ewe. A number of 
small lochs within the district now being dealt with could not be 
surveyed for lack of boats. 

* The smaller Loch Garbhaig lying to the west of Loch Maree was not sounded. 



THE FRESH- WATER LOCHS OF SCOTLAND. 211 

The geology of this district is described by Drs. Peach and Home, 
their important contribution being illustrated by a special geological 
map. 

Loch Maree (see Plates XLVI. and XLVII.). The loch derives its 
name from Saint Maelrubha, who in 671 A.D. left Bangor, and after 
founding one church at Applecross, founded another on Isle Maree. 
It is the largest sheet of fresh water in Scotland north of Loch Ness, 
and trends in a north-west and south-east direction. 

On the north-east side of the loch, and parallel to it, runs a grand 
series of mountains Beinn Airidh Charr, Meall Mheannidh, Beinn 
Lair, Slioch, Sgurr an Tuill Bhain, and Beinn a Mhuinidh ; the slope 
for the first 1000 feet all along this north-eastern shore is very steep, in 
many places exceeding 45. To the south-west rise Beinn Eighe, Beinn 
a Chearcaill, and Beinn an Eoin ; the sharp ridge of the former, com- 
posed of white quartzite, forms an especially fine object from the loch to 
the north of the Gruididh. But the two most striking features of Loch 
Maree are Slioch and Isle Maree; the huge sugar-loaf form of Slioch 
is conspicuous from almost every part of the loch, and, though one of 
the smaller islands, Isle Maree, owing to the large number of trees 
growing upon it, stands out against the dark background of the heather- 
covered islands and the cliffs of the north-eastern shore. 

The great feature 'of Loch Maree is the large number and great 
area of its islands. Prof. Penck, in his work on the Lake of Constance, 
lays great stress on the ' ' insulosity, " i.e., "the proportion of the area 
of the islands to that of the water surface ; " this in Loch Maree is 0'09, 
or three times as great as that of the Lake of Cheim (0'03), and nine 
times as great as that of the Lake of Constance (0-01). Its insulosity is 
also greater than that of any other large lake in Great Britain, that of 
Loch Lomond being 0'08, though it is surpassed in this respect by one 
of the small lochs in the Assynt district (Loch Crocach, whose insulosity 
is 0-091). 

Many of the islands were joined together when the Lake Survey 
visited the loch, owing to the low level of the water. A few small 
rocks and reefs occur out in the channel to the north of the main 
group of islands and removed some considerable distance from the rest. 
Large numbers of the Lesser Black-Backed Gull (Larus fuscus) breed 
on the larger islands, and two pairs and young of the Greater Black- 
Backed Gull (Larus marinus) were observed on two of the smaller islets. 
Isle Maree, Eilean Ghruididh, Eilean Subhainn, and Eilean Ruairid 
Bheag have been used at one time as fortresses or habitations. 

The level of Loch Maree was found by the Ordnance Surveyors to 
be 32-1 feet above sea-level on September 15, 1870; on July 16, 1902, 
the surface of the water was 29-5 feet above sea-level. The loch was 
surveyed on July 16 to 24, 1902, and the water remained at very nearly 



212 



BATHYMETRICAL SURVEY OF 



the same level during the nine days spent in surveying it. The average 
height of the water for the whole of the year is about 1 J feet above the 
level on July 16, 1902 ; the water has been known to rise 9 feet higher 
and to fall 1 foot lower than the level on this date. 




Bartholomew 



9 ! ? * * 



FIG. 37. INDEX MAP OF THE EWE BASIN. 



^Eng Miles 



Before dealing with the statistics of Loch Maree, it is necessary to 
state that there has been included in the loch a large portion of the 
piece of water styled " River Ewe;" soundings were taken in the 
so-called river, and depths of over 30 feet were obtained in places down 
to beyond the commencement of the Pool Crofts. Just above the partly 






THE FRESH- WATER LOCHS OF SCOTLAND. 213 

artificial dam depths of 37 and 35 feet were obtained, and these would 
seem to point to the fact that down to here the " river " is nothing 
more than an arm of the loch, with a current flowing along it to the 
outfall. That this place is the beginning of the river was evidently 
the opinion in past time, for it was here that the old iron-workers 
built their dam to obtain water for working "A Cheardach Ruardh" 
(The Red Smiddy). 

The length of the loch as thus defined is 13 J miles, and the 
maximum breadth rather over 2 miles. The mean breadth is nine- 
tenths of a mile, being 7 per cent, of the length. Its waters cover an 
area of over 11 square miles, and the islands nearly 1 square mile. 
Loch Maree has a large shore development, i.e., the length of the 
shore-line is much greater than the circumference of a circle whose 
area is equal to that of the loch. The shore development is 3'15, being 
greater than that of any other large loch in Scotland. The drainage 
area is 171 square miles, or 15 times the area of the loch. 

Twelve hundred soundings were taken in Loch Maree, and the 
greatest depth obtained was 367 feet, in the middle of the loch to the 
south-west of Rudh' a' Ghuibhais ; the bottom of the loch here is thus 
337J feet below sea-level. The volume of water is estimated at over 
38,500 millions of cubic feet, and the mean depth at 125 feet (34 per 
cent, of the maximum depth). The breadth of the loch at the position 
of the deepest sounding is seven times the depth. 

Loch Maree is divided into three main basins (1) that extending 
from Isle Maree to the south-east end of the loch, which may be called 
the " Ghruididh basin;" (2) that lying to the south of the islands, 
which may be called the ' ' Slattadale basin ; ' ' and (3) that extending 
from the north-east of Eilean Ruairid Mor to the north-west end of the 
loch, which may be called the "Ardlair basin. " 

(1) The Ghruididh basin. This basin is the largest and deepest of 
the three. The 200-feet area extends from a quarter of a mile to the 
east of Isle Maree to about half a mile from the south-east end of the 
loch, and has a length of 6J miles, its average width being about three- 
quarters of a mile. The main 300-feet basin has a length of 2 miles 
and a mean breadth of about a quarter of a mile ; it extends from south 
of Coppachy to north of milestone 3 miles from Kinlochewe. There is 
another smaller 300-feet area a little to the north-west of the main 
area. The 350-feet basin has a length of one mile and an average 
width of one-sixth of a mile ; it extends from north of milestone 5 miles 
from Kinlochewe to north of milestone 4 miles from Kinlochewe. 

The greatest depth is 367 feet, this depth being obtained in the 
middle of the loch to the south of Rudh' a' Ghuibhais. The deepest 
part of the loch thus lies between the two faults shown on the Geological 
Map, one of which cuts the loch a little to the south-east of the river 
Ghruididh on the south-west shore, and the other where the stream from 



214 



BATHYMETRICAL SURVEY OF 



Lochan Fada enters the loch on the north-east shore. The deepest part 
of this whole basin occurs where the great mass of Slioch on the one 
side, and the heights of the Kinlochewe forest on the other, rise steeply 
up from the shore, and, as it were, compress the valley into its narrowest 
limits. 

This basin has a typical " cauldron " shape, which is brought out 
in the section on the map, the slope on both sides down to the 350- 
feet contour-line being one of 26J; the flat portion in the middle is 
about 300 yards broad at the deepest place. The slope up to the 1000- 
feet contour-line is one of 24J on the north-east shore, and one of 14 
on the south-west shore. 




FIG. 38. LOCH MAREE, THE ISLANDS IN THE MIDDLE DISTANCE. 

(Photograph by Mr. J. A. Harvie-Brown, F.Z.S.) 



It should be noted that the floor of the loch rises steeply where the 
second fault alluded to cuts it, that part of the loch lying to the south- 
east of this fault being very shallow. This feature is also seen where 
the same fault cuts the east end of Lochan Fada. 

In Loch Maree a large number of the streams have formed very 
decided alluvial cones; e.g. the large one at the mouth of the Ghruididh 
river. This feature is much more marked in Loch Maree than in the 
majority of lochs. Other features of interest in this basin are the 
comparatively deep soundings in Ob nam Muc and the inlet to the 
south-east of this; and the curious hill on the bottom of the loch to 
the south of Letterewe (300 yards from the shore), the summit of which 
is covered by 44 feet of water. 



THE FRESH- WATER LOCHS OF SCOTLAND. 215 

(2) The Slattadale basiu. This basin extends from west of Eilean 
Ruairid Mor to south of Eilean Subhainn. The 150-feet area has a 
length of 2 miles and a mean breadth of a quarter of a mile. The curve 
traced out by this contour to the east of the Slattadale river is very 
remarkable ; the extension of the shallower part of the loch into the 
150-feet area is in the direction of the Slattadale river, but the sound- 
ings nearer to the shore give no indication that this bank is due to the 
material brought down by the river. The 200-feet area extends from 
south of Eilean Ruairid Mor to north of Stalla nam Manach, its length 
being nearly 1| miles, and its average breadth about 150 yards. The 
greatest depth is 232 feet in the extreme north-west of the basin. In 
a line with the curious indentation in the 150-feet contour-line the 
200-feet basin is very narrow and shallow (202 feet). 

Comparatively deep soundings were obtained in all the channels 
extending into the islands, and it is noteworthy that the long and 
narrow passage between Eilean Subhainn and Garbh Eilean lies in 
a line with the narrow prolongation of deeper water from Rudha 
Chailleach into the shallow water north of the islands. 

Ob na h-Innse Moire in Eilean Subhainn was cut off from the main 
part of the loch by a sand-bar. This was also the case with the inlet to 
the north-west of Ob na h-Innse Moire, but this inlet had its surface 
covered with weeds and boulders. 

(3) The Ardlair basin. The outline of this basin is also very 
irregular, and the bottom more so than in either of the other basins. 
The 100-feet area has a length of 3J miles and a mean breadth of 
three-quarters of a mile. The 200-feet area has a length of 2^ miles and 
an average breadth of one-third of a mile. The length of the 250-feet 
basin is two-thirds of a mile and the average breadth a quarter of a 
mile. The greatest depth in this basin is 285 feet, occurring about 
700 yards to the south-east of Rudh' Aird an Anail. 

In this basin the contour-lines run very close to the north-eastern 
shore in the western and central parts of the basin, but spread out 
towards the eastern part. Again, they run very close to the shore 
round the western coast of Eilean Ruairid Mor and round Rudh' Aird 
an Anail. They have a very sinuous outline in the eastern part of the 
basin. 

As stated above, the floor of this basin is very irregular; several 
small hills rise above the general level of the bottom, as that to the 
south of Ardlair and that to the east of Rudh' Aird an Anail. The 
north-western extension of this basin, called " River Ewe," has 
already been noticed. 

There remain for consideration the ridges between the basins and 
the large tract of shallow water to the north of the islands. The 
ridge which runs across from Eilean Ruairid Mor to the mouth of 
Allt na Doire is very marked. The lowest part of the ridge is 83 feet 



216 BATHYMETRICAL SURVEY OF 

below the surface of Loch Maree, whilst the distance between the two 
100-feet contour-lines at this place is 120 yards, and that between the 
two 150-feet contours is 550 yards. 

The shallow water to the north of the islands is much more remark- 
able. A large part of this area is under 50 feet in depth, and the 
deepest water that occurs anywhere between Creag Tharbh and Rudha 
Chailleach is 79 feet, though it is along this northern channel that the 
great fault must run. Right in the middle of the channel, underneath 
Creag Tarbh, the water is only 41 feet in depth ; the hills on the north 
shore rise steeply up to heights of over 2000 feet in places, and the 
slope up to the 1000-feet contour-line is at an angle of 45 ; hence the 
difference between the sub-aerial and the sub-aqueous slopes is in this 
place very marked. Rudha Chailleach (the witch's point) is a narrow 
spit of shingle stretching out to a considerable distance into the loch, 
with deep water close to the shore. From this point a narrow channel 
of deeper water projects right across the loch towards the opening 
between Eilean Subhainn and Garbh Eilean. 

The ridge between the Slattadale and Ghruididh basins is merely a 
continuation of the islands. The depths on it are much less than on 
either of the other ridges; there is, however, a fairly deep channel, 
through which the steamer passes, ranging in depth from 62 feet to 
28 feet; this channel is narrowest and shallowest between Isle Maree 
and Eilean Eachainn. To the south of Isle Maree is a large sand-flat, 
which in July, 1902, was covered by less than a foot of water, and on 
which were many boulders rising above the surface of the water. 

The areas between the consecutive contour-lines, and the per- 
centages to the total area of the loch, are as follows : 

to 50 feet 2090 acres 29 '6 per cent. 

50,, 100 , 1283 18-2 



100,, 150 

150 200 

200 250 

250,, 300 

300,, 350 

Over 350 



1066 15-1 

877 12-4 

977 13-9 

412 5-8 

254 3-6 

99 , 1-4 



7058 100-0 



It will be observed that the zone between 200 and 250 feet is larger 
than that between 150 and 200 feet, otherwise the areas between the 
contour-lines drawn in at equal intervals decrease gradually with 
increase of depth. 

The Small Loch on Eilean Subhainn. Apparently this loch has not 
been considered important enough to receive a name, but the fact that 
it had the appearance of being of some depth, whereas the other lochs 
on the islands on Loch Maree are overgrown with weeds or moss, 



THE FRESH- WATER LOCHS OF SCOTLAND. 217 

induced the Lake Survey to sound it. The trouble taken was well 
repaid by the curious nature of the bottom revealed by the soundings.* 

Eilean Subhainn is 292J acres in area, its shore-line being very 
irregular. The surface of the ground is uneven, though nowhere except 
in the south-east corner is it very elevated ; here, however, a small hill 
rises to a height of 84 feet above the level of Loch Maree. The greater 
part of the island is not more than 30 to 40 feet above Loch Maree, 
this rise for the most part taking place in the first 30 yards, and in 
some places there are vertical cliffs from 20 to 30 feet in height. In 
these cliffs it is seen that the island is composed of Torridon Sandstone ; 
the rock does not appear elsewhere except around the little loch, the 
island being covered with peat, with a considerable number of fir trees 
round the shore and in the south-east corner. 

The loch lies in a small hollow in the centre of the island, being 
situated about a quarter of a mile from the south-east shore, and one- 
third of a mile from the west shore of the island, and about 150 yards 
from the Lily Loch. Its level was determined on July 24, 1902, to 
be 57*4 feet above sea-level, and 27'9 feet above the surface of Loch 
Maree. 

The loch trends in an east and west direction, and its length is a 
little over 250 yards ; its maximum breadth is about 100 yards, and the 
mean breadth about 70 yards. Its waters cover an area of nearly 5 
acres, and its drainage area is ten times greater, or 51 acres; the shore 
development is 1-62 and the insulosity 0-02. The maximum depth is 
64 feet, and hence the bottom of the loch is 30 feet below the level 
of Loch Maree, and 6J feet below sea-level. The volume of water 
contained in the loch is estimated at 6 millions of cubic feet, and the 
mean depth at 46^ feet. 

The loch is fairly regular in outline, and has three small islands in 
it. The deepest part is a mere hole near the western end ; on the ridge 
running across from the island near the north shore to the island with 
the tree there is only 5 feet of water, but there is a considerable depth 
of mud. In the eastern part of the loch depths of 12 feet were met 
with. Eighty -five per cent, of the total area of the loch is less than 
50 feet in depth. This loch is the only one situated on an island in 
another loch which has been visited by the Lake Survey. It was 
surveyed on July 24, 1902. 

Temperature Observations. Many surface temperatures were taken 
in Loch Maree between July 16 and 24, 1902, the greatest range 
observed being from 53-3 off Letterewe at 11 a.m. on the 21st, to 57-0 
at Talladale at 7 p.m. on the 22nd. The surface temperature in the 
south-east end of the loch was almost always higher than that in the 



* The method of sounding out this loch is interesting: it was found impossible to 
transport a boat to the loch, and Mr. Garrett took soundings by hand while swimming. 



218 



BATHYMETRICAL SURVEY OF 



north-west end, owing to the north-west winds prevailing during the 
time the Lake Survey was on the loch. For instance, on July 19 the 
temperature of the surface north-west of Rudh' Aird an Anail was 
53-9 at 3 p.m., and off Ardlair it was 54-0 at 4 p.m., whilst at 
3.15 p.m. it was 55*3 to the south-east of Fhasaigh. 

Five serial observations were taken on July 19 and 21, as given in 
the following table : 



Depth 
in 

feet. 


Loch Maree, oppo- 
site Pool Crofts, 
July 19, 1902, 
12 noon. No 
wind. 


Loch Maree, S.W. 
of E. Ruairid 
M6r, July 19, 
1902, 6 p.m. 
Stiff N. breeze. 


Loch Maree, oppo- 
site Letterewe, 
July 21, 1902, 
12.45 p.m. 


Loch Maree. N. of 
E. Ruairid M6r, 
July 21, 1902, 
1 p.m. Light 
N.W. breeze. 


Loch Maree, off 
Rudh' a' Ghui- 
bhais, July 21, 
1902. 6 p.m. 
Moderate N.W. 
wind. 





o 
53-5 


o 

54'7 


53-9 


53-9 


53-9 




54-5 


5 






53-8 


... 




54-2 


7 


... 


... 










10 


... 


... 


53 : 6 


53 : 7 


53-7 


54-2 


15 


53-6 


54-7 


53'5 


53-3 


53-4 




20 




... 


53-5 






54-2 


25 




54-0 




53-5 


53 : 7 


... 


30 


53-6 




53-3 


V 


54-0 


35 


... 






53-2 


... 


50 




53 : 


53-1 


53-0 


54 : 


75 




50-0 


50-8 


50-3 


53-6 


80 




... 


... 


... 


... 


85 










49-6 


100 




48 '-0 


49-0 


48"2 


48-0 


150 




48-1 


46-9 


46-6 


46-4 


200 


... 


47-0 


45-9 


46-0 


45-9 


250 




... 


45-4 






300 


... 








45-6 


350 


... 


... 


... 


... 


45-5 



Below the surface the fall in temperature was slow down to about 
50 feet, when the fall became very rapid down to 150 feet, and then 
slow again to the bottom. Though these are the characteristics of the 
three series taken on the 21st, that taken on the 19th to the south of 
Eilean Ruairid Mor in the Slattadale basin does not agree with the 
others. In this case there was a rapid fall from 20 to 100 feet, and 
then a slight rise in temperature to 150 feet, and then a slow fall again 
to 200 feet. 

The series taken to the north of Eilean Ruairid Mor on the 21st is 
interesting on account of the decided inversion at 25 feet. Though 
these inversions of temperature have occasionally been observed, they 
are by no means common. In this case it was noticed that the tempera- 
ture fell from 53'9 at the surface to 53'7 at 10 feet, and to 53'3 at 15 
feet, and then rose to 53'5 at 25 feet, and then fell again steadily below 
this depth. The series down to 25 feet was repeated with the results 
shown in the second column under this head, which proved that the 
inversion, though small, was real and not due to the instrument. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



219 



Lochan Fada (see Plate XLVIIL). Lochan Fada (i.e., the long 
loch) is the largest of its name. It is situated about 3 miles to the 
north-east of the upper end of Loch Maree, and runs parallel to it for 
a distance of 4 miles. The scenery around Lochan Fada is of the most 
magnificent description, Slioch and Beinn Lair overlooking it on the 
south-west shore, and Beinn Tharsuinn and A Mhaighdean on the north- 
east shore. The ridge between Lochan Fada and Gorm Loch Mor is 
particularly noticeable ; the rise from the loch is 750 feet in 350 yards, 
and the top of the ridge is exactly like a knife-edge. The crags on the 





FIG. 39. LOCH FADA, LOOKING NORTH, SHOWING RIDGE. 

(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.S.E.) 



south-west shore are very bold and wild, being composed of the Beinn 
Lair sill of hornblende-schist, and extend from between Lochan Fada 
and Loch Garbhaig to south of Loch Fionn. When standing above the 
north-west end of the loch, the outlet to the south is not suspected; 
the loch appears to drain away down the continuation of the glen into 
Glen Na Muic. Doubtless at one time this was the outlet of the loch, 
for the col here between Lochan Sgeireach and L'och Gleann na Muic 
is only 13 feet above the level of Lochan Fada. But Abhuinn an 
Fhasaigh, having a much shorter course than Abhuinn Gleann na Muic, 
has been able to cut back much more rapidly, and perhaps all the 
more so since its course lies along the line of fault, which runs from 



220 BATHYMETRICAL SURVEY OF 

Loch Meallan an Fhudair to Loch Maree, and has tapped Lochan Fada, 
slightly lowering its level, thus beheading Abhuinn Gleann na Muic. 

The height of the loch above sea-level was not determined by the 
Ordnance Survey, nor by the Lake Survey when sounded on July 25 
to 28, 1902, owing to absence of bench-marks, but, judging from the 
spot-levels and the 1000-feet contour-line, its level must be about 1005 
or 1006 feet above the sea. 

The length of Lochan Fada is 3| miles, and its maximum breadth 
nearly two-thirds of a mile; the mean breadth is over one-third of a 
mile. Its waters cover an area of nearly 1J square miles, and it drains 
an area 6J times greater, or over 9J square miles. The maximum 
depth is 248 feet ; this occurs in the centre of the loch off the mouth of 
Allt Meallan a' Chruidh. The mean depth is estimated at 102 feet, and 
the volume at 4091 millions of cubic feet. The breadth of the loch at 
the position of the deepest sounding is twelve times the depth. The 
shore development is 2-16, and the insulosity is nil ; Lochan Fada, like 
so many of the larger lochs, has not a single island. 

The bottom of Lochan Fada is very regular, the 50-feet and 100-feet 
areas being continuous, and extending almost from one end of the loch 
to the other. The main 150-feet area extends from west of Claona to 
the narrower part of the loch, and has a length of 1J miles; there is t* 
small 150-feet area near the south-east end of the loch. The 200-feet 
area extends from south-west of Claona to west of Allt na Botaig ; its 
length is one mile, and average width 280 yards. 

The areas between the consecutive contour-lines, and the per- 
centages to the total area of the loch, are as follows : 

Oto 60 feet 230 acres 25 -0 per cent. 

50,, 100 ,, 236 25-7 

100,, 150 263 28-7 

150,, 200 100 10-8 

Over 200 , 90 , 9 '8 



919 , 100-0 



It is unusual to observe, on proceeding from the shore into deeper 
water, an increasing area between the contour-lines drawn at regular 
intervals, as in the case of Lochan Fada, and indicates an average steep 
slope near shore. A glance at the map shows that the 50-feet contour 
follows closely the outline of the loch, and in places approaches very 
close to the shore. 

Seiche. On July 28, beginning at 1 p.m., a well-marked seiche was 
observed in Lochan Fada in a sheltered bay at the south-west end of 
the loch ; the wind was strong from the west. The amplitude was half 
an inch, and the period about 11-6 minutes; but this oscillation was so 
broken up by two other oscillations, whose periods were about 2J 



THE FRESH- WATER LOCHS OF SCOTLAND. 221 

minutes and 1 minute respectively, that the whole effect was extremely 
complicated, and no calculations could be made from the observations. 
Temperature Observations. The temperatures taken in Lochan Fada 
are extremely interesting, because they indicate a much lower tempe- 
rature than was observed in any of the other lochs in the district at the 
same time of the year, as shown by the following series taken at 6.40 
p.m. on July 28, 1902, to the south of Allt Meallan a' Chruidh : 

Surface 51'l Fahr. 

10 feet 51'l 

20 ... 51'l 

50 51-0 

75 45-8 

100 45-0 

150 44-3 

220 44-l 

This series indicates an almost constant temperature down to 50 
feet, then a fall of 5-2 between 50 and 75 feet (a fall exceeding 1-0 per 
5 feet of depth), and then a slight decrease of l-7 down to the bottom in 
220 feet. Compared with the larger and deeper Loch Maree, the water 
in Lochan Fada was found to be colder at all depths than that in Loch 
Maree : thus the surface of Lochan Fada had a temperature about 3| 
lower than was observed in the surface waters of Loch Maree a week 
earlier, and at the bottom of Lochan Fada, in 220 feet, the temperature 
was found to be about 1J lower than at the bottom of Loch Maree in 
350 feet. This is probably due to the fact that Lochan Fada is very 
deep, considering its area, and therefore a large volume of water has to 
be warmed, while only a comparatively limited area is exposed to the 
heating agencies. 

Loch Garbhaig (see Plate XLVL). Loch Garbhaig lies between 
Lochan Fada and Loch Maree, about half a mile from the former and 
1^ miles from the latter. It drains into Loch Maree by the Amhainn 
na Fuirneis, which leaves the loch at its western end, and, flowing in a 
westerly direction, enters Loch Maree between Furness and Letterewe. 
The ground at the eastern end is not much elevated above the surface of 
the loch, the col leading over to Lochan Fada, but on the south side 
Slioch rises up from the shore to a height of 3200 feet, and on the north 
side the high ground to the east of Beinn Lair rises to over 2500 feet. 
The most noticeable feature of the surrounding country is its bareness. 
The height of the loch above the sea was not determined by levelling 
when surveyed on July 25, 1902, but from the contour-lines the level 
is probably between 1005 and 1015 feet. 

Loch Garbhaig is over a mile in length, with a maximum breadth 
of nearly one-third of a mile, the mean breadth being one-fifth of a 
mile. Its waters cover an area of about 148 acres, and it drains an 



222 BATHYMETRICAL SURVEY OF 

area 10J times greater, or nearly 2 square miles. The maximum 
depth of 93 feet was observed about 300 yards from the eastern shore. 
The volume of water contained in the loch is estimateU at 228 millions 
of cubic feet, and the mean depth at 35| feet. The breadth of the 
loch at the position of the deepest sounding is sixteen times the depth. 
The shore development is 2*15, and the insulosity 0*014. 

The 25-feet area is continuous, passing to the north of the large 
island. The 50- and 75-feet areas lie in the eastern part of the loch, 
though there is one sounding of 50 feet in the extreme west. The 
50-feet area has a length of nearly half a mile, and extends to within 
40 yards of the eastern shore, while the 75-feet area is a quarter of 
a mile in length. The areas between the consecutive contour-lines, 
and the percentages to the total area of the loch, are as follows : 

to 25 feet 67 acres 45 '4 per cent. 

25,, 50 42 28-3 

50 75 20 13-3 

Over 75 , 19 , 12'5 



148 , 100-0 



The temperature of the surface water in Loch Garbhaig at 4 p.m. 
on July 25, 1902, was 54 0> 9 Fahr., or nearly 4 warmer than that 
observed in Lochan Fada, which lies at the same elevation; no serial 
temperatures were taken. 

Loch Glair (see Plate XLIX.). Loch Clair is situated about three 
miles to the south-west of Kinlochewe, at the head of Loch Maree. The 
ground to the north and west rises to the heights of Beinn Eighe and 
Sgurr Dubh, the lower ground being covered by moraines. It was 
surveyed on July 24, 1902, and the elevation of the water surface above 
the sea was determined by levelling from bench-mark as being 303' 1 
feet. 

Loch Clair is over 1J miles in length, with a maximum breadth of 
about 600 yards, the mean breadth being about 300 yards. Its waters 
cover an area of about 160 acres (a quarter of a square mile), and it 
drains directly an area of 6J square miles, but since it receives the 
outflow from Loch Coulin its total drainage area is 20J square miles 
an area 83 times greater than that of the loch. The maximum 
depth is identical with that observed in Loch Garbhaig, viz., 93 feet, 
and occurs about 150 yards from the eastern shore off Creag naRianaich. 
The volume is estimated at 287 millions of cubic feet, and the mean 
depth at 42 feet. The breadth of the loch at the position of the deepest 
sounding is sixteen times the depth. The shore development is 2*01, 
and the insulosity very small (O'OOl), there being only two small 
islands in the loch. 



THE FRESH-WATER LOCHS OF SCOTLAND. 223 

The bottom of Loch Clair is fairly regular, the deeper water being 
found in the wide south-eastern portion, where there is a 50-feet basin 
about half a mile in length, enclosing a 75-feet basin one-third of a 
mile in length. The 25-feet area is continuous, passing to the south 
of the larger island, between which and the southern shore a depth of 
46 feet was found. The areas between the consecutive contour-lines, 
and the percentages to the total area of the loch, are as follows: 

to 25 feet 58 acres 34 - 9 per cent. 

-'"> 50 38 24-4 

50,, 75 41 25-9 

Over 75 , 23 , 14'8 



160 100-0 



It will be observed that the zone between 25 and 50 feet is smaller 
than the zone between 50 and 75 feet, indicating that the average 
slope is steeper in the shallower zone. 

Temperature Observations. A series of temperatures taken at 4 p.m. 
on July 24, 1902, in the deep water gave the following results : 

Surface ... 57 0< OFahr. 

5 feet 57'7 

10 ,, ... 57'2 

20 ,, 57'2 ,, 

30 , 540 

40 49'9 

50 48'7 

85 48-0 

It will be noticed that the temperature of the water between 
5 and 20 feet was higher than that at the surface, the highest reading 
being at 5 feet. Between 20 and 30 feet a fall of 3'2 is recorded, and 
between 30 and 40 feet a fall of 4-l, a total fall of 7'3 in 20 feet, the 
extreme range shown by the observations being 9-7. 

Loch Coulin (see Plate XLIX.). Loch Coulin is situated 300 yards 
to the south-east of Loch Clair, into which it drains. Doubtless, in very 
recent times, they formed one loch, for the ground between them is low 
and alluvial. To the south-west and south-east rise Beinn Liath Mor 
and Carn Breac. Loch Couliu is very much overgrown with weeds, 
especially in the narrow north-western portion. It was surveyed on 
July 24, 1902, the water surface being 304-6 feet above sea-level, or 
H feet above the level of Loch Clair. 

Loch Coulin is 1J miles in length, with a maximum breadth of one- 
third of a mile, the mean breadth being about 250 yards. Its waters 
cover an area of 113 acres, and it drains an area 78 times greater, or 
14 square miles. The maximum depth of 49 feet occurs near the 
centre of the broader south-eastern portion of the loch. The volume 



224 



BATHYMETRICAL SURVEY OF 



of water is estimated at 90 million cubic feet, and the mean depth 
at 18 feet. The breadth of the loch at the position of the deepest 
sounding is 31 times the depth. The shore development is 2-45, and 
the insulosity nil. 

Loch Coulin is very irregular in outline, and is cut up into three 
basins, the north-western basin having a maximum depth of 32 feet, 
and the central basin a maximum of 22 feet. The main basin is 
confined to the broad south-eastern part of the loch, and the contour- 
lines approach very close to the eastern shore, off which the slope is 
steep. There are two isolated soundings less than 25 feet within this 
area, and deep water is found at the entrance of the river Coulin. 




FIG. 40. LOCH COULIN, LOOKING NORTH. 

(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.S.E.) 



The area covered by less than 25 feet of water is over 80 acres, or 72 
per cent, of the entire area of the loch. 

Temperature Observations. A series of temperatures was taken in 
the deep part of the loch at 5 p.m. on July 24, 1902, with the following 
results : 



Surface 
5 feet 
10 
15 
'20 
30 
40 , 



57'OFahr. 

57 -0 

57'l 

57 -0 

55 -5 

54'8 
53 -0 



THE FRESH- WATER LOCHS OF SCOTLAND. 225 

The temperature was found to be constant from the surface to a 
depth of 15 feet, thence the temperature fell 4 to the bottom in 40 
feet. 

Loch Tollie (see Plate XLVII.). Loch Tollie is situated 1J miles to 
the west of the lower end of Loch Maree, and drains into its north- 
western arm. The ground immediately surrounding the loch is low, 
though Meall Airidh Mhic Criadh to the south-west, and Creag Mhor 
Thollie to the south-east, rise to over 1100 feet. The loch is roughly 
elliptical in outline, the major axis having an east and west direction. 
One of the islands near the northern shore was for some time a strong- 
hold of the McLeods. 

Loch Tollie was surveyed on July 29, 1902, the elevation of the lake- 
surface being 387 - feet above sea-level ; when visited by the Ordnance 
Survey officers on November 13, 1869, the level was found to be 387-7 
feet. The water must at one time have stood at a higher level, for at 
the east end, where the stream leaves the loch, there are the remains of 
a dam (now fast disappearing), which held up the water for supplying 
a mill farther down the burn. 

Loch Tollie is under a mile in length, with a maximum breadth of 
about 800 yards, the mean breadth being about 500 yards. Its waters 
cover an area of about 169 acres (a quarter of a square mile), and it 
drains an area eight times greater, or 2 square miles. The maximum 
depth of 86 feet was observed in the centre of the loch off the mouth 
of the Allt Loch Laraig. The volume of water is estimated at 244 
millions of cubic feet, and the mean depth at 33 feet. The breadth of 
the loch at the position of the deepest sounding is 27 times the depth. 
The shore development is small (I'll), and the insulosity 0'002. The 
deeper water occurs in the western part of the loch, though the 25-feet 
area sends a narrow tongue into the eastern part. The 75-feet area 
in the centre of the loch is small, with a narrow tongue extend- 
ing towards the northern shore. The areas between the consecutive 
contour-lines, and the percentages to the total area of the loch, are 
as follows : 

to 25 feet 81 acres 48'0 per cent. 

25,, 50 43 25-6 

50,, 75 35 20-6 

Over 75 , 10 , 58 



169 ,, 100-0 



Temperature Observations. The following series of temperatures 
was taken in the centre of the loch at 6 p.m. on July 29, 
1902: 



226 BATHYMETRICAL SURVEY OF 

Surface 55'5 Fahr. 

5 feet 55-5 

10 55-3 ,, 

20 55 -3 

30 ,, 55-2 ,, 

50 55'l 

60 ,, 54 C> 3 ,, 

70 ,, 50 0> 9 ,, 

This series shows that the temperature was practically constant 
down to 50 feet, the fall being less than J, thence a fall of 0-8 between 
50 and 60 feet, and then a rapid fall of 3 0> 4 between 60 and 70 feet. 

Loch Kernsary (see Plate XL VII.). Loch Kernsary is situated to 
the north-east of Inveran, at the foot of Loch Maree, into which it 
drains through the little Loch Poll Uidhe a' Chro' and the Inveran 
river. There was no boat passage into Poll Uidhe a' Chro', and it was 
found impossible to carry the boat across. The ground around Loch 
Kernsary is low, except to the north, where Meall an Leathaid Dharaich 
rises to over 400 feet. The island near the south-western shore in the 
main portion of the loch is an artificial crannog, but nothing is known 
of its history N 

Loch Kernsary was surveyed on July 25 and 26, 1902 ; the elevation 
of the water-surface above the sea was determined, by levelling from 
Loch Maree, as being 68'0 feet. The keeper stated that the water would 
rise 2J feet above, and fall 1 foot below this level, but a drift-mark 
was observed 8-4 feet above the surface of the water. 

Loch Kernsary is about 1 J miles in length, with a maximum breadth 
of nearly half a mile, the mean breadth being about 350 yards. Its 
waters cover an area of about 200 acres, and it drains directly an area 
of nearly 7| square miles, but since it receives the outflow from Loch 
Ghiuragarstidh, its total drainage area is over 8J square miles an area 
27J times greater than that of the loch. The maximum depth of 93 
feet was observed about 250 yards from the north-western extremity of 
the loch. The volume of water is estimated at 333 million cubic feet, 
and the mean depth at 38 feet. The breadth of the loch at the position 
of the deepest sounding is ten times the depth. The shore development 
is 2*51, and the insulosity 0*008. 

The floor of Loch Kernsary is rather irregular, there being two 
25-feet areas and four 50-feet areas. The main 25-feet area extends 
throughout the greater part of the loch, while the smaller one lies in 
the south-western part of the loch. Three of the 50-feet areas are 
enclosed by the main 25-feet area : the north-western one containing 
the deepest water in the loch, the central one having a maximum depth 
of 66 feet, and the south-eastern one a maximum depth of 69 feet, 
therefore falling just below sea-level; the fourth 50-feet area, based 



THE FRESH-WATER LOCHS OF SCOTLAND. 227 

on soundings of 51 and 53 feet, lies in the centre of the south-western 
part of the loch. The 75-feet area is situated in the north-western part 
of the loch, and sinks below sea-level, the deepest spot being 25 feet 
below the level of the sea. 

The areas between the consecutive contour-lines, and the percentages 
to the total area of the loch, are as follows : 

to 25 feet 72 acres 35 '8 per cent. 

25,, 50 69 34-4 

50,, 75 39 19-8 

Over 75 , 20 . lO'O 



200 , 100-0 



Thus 70 per cent, of the lake-floor is covered by less than 50 feet of 
water. 

Temperature Observations. A series of temperatures was taken in 
the deep part of the loch at 2.30 p.m. on July 25, 1902, with the 
following results : 

Surface 57'0 Fahr. 

10 feet 57-0 

25 56-8 

50 53'0 

80 ,, 50-2 

This series shows an almost constant temperature down to 25 feet, 
then a rapid fall of 3'8 between 25 and 50 feet, and a further fall of 
2-8 between 50 and 80 feet. 

Loch Gliiuragarstidh (see Plate XLVII.). Loch Ghiuragarstidh 
lies about half a mile to the north of Loch Kernsary, into which it 
drains by the Allt Loch Ghiuragarstidh. The islands are covered by a 
few feet of peat and soil, and have many fir trees growing on them. 
The loch was surveyed on July 28, 1902; the elevation of the lake- 
surface was determined, by levelling from Loch Kernsary, as being 
11 6' 7 feet above mean sea-level. 

Loch Ghiuragarstidh is about 1200 yards in length, with a maximum 
breadth of about 370 yards, the mean breadth being about 230 yards. 
Its waters cover an area of 58 acres, and it drains an area nearly ten 
times greater, or about 560 acres. The volume of water is estimated 
at 23 million cubic feet, and the mean depth at 9 feet. The breadth of 
the loch at the position of the deepest sounding is 27 times the depth. 
The shore development is 1-63, and the insulosity 0'028. The bottom is 
very irregular in the southern half of the loch, large boulders and reefs 
rising above the surface of the water in many places. In the northern 
half the lake-floor is more regular, and it is only in this part that the 
depth exceeds 10 feet, the maximum depth of 37 feet having been 



228 BATHYMETRICAL SURVEY OF 

observed in the centre of the loch near the northern end. The area of 
the lake-floor covered by less than 25 feet of water is about 56 acres, or 
96 per cent, of the total area. 

Temperature Observations. Temperatures taken at 5 p.m. on July 
28, 1902, in the deep part of the loch gave the following results : 

Surface 57'5 Fahr. 

5 feet 57'5 ,, 

7 57'5 

15 57'l 

25 ... 56'0 ,, 

Loch a' Bhaid-Luachraich (see Plate L.). Loch a' Bhaid-Luachraich 
(or Goose Loch) lies about a mile to the east of Loch Ewe, into which 
it drains at Aultbea by the Allt Bheithe. It is surrounded by low, 
rounded hills, steep only towards the south-east, covered with peat or 
morainic material. It is extremely irregular in outline, and in fact 
may almost be looked upon as two lochs with a connecting arm. The 
south-western part is shallow, the maximum depth observed in it 
being 43 feet, while the north-eastern part is much deeper, having a 
maximum depth of 143 feet; the maximum depth observed in the 
connecting arm was 15 feet. The lower part where the stream leaves 
the loch is thickly overgrown with reeds and rushes, and weeds are 
abundant in the two bays at the head of the loch. It was surveyed 
on July 29 and 30, 1902, and the elevation was determined, by levelling 
from bench-mark, as being 309*6 feet above the sea; when levelled by 
the officers of the Ordnance Survey on August 3, 1870, the elevation 
was found to be 310*5 feet above sea-level. 

Loch a' Bhaid-Luachraich is over 1 J miles in length, and over a mile 
in maximum breadth, with a mean breadth of one-third of a mile. It 
covers an area of half a square mile, and it drains directly an area of 
3J square miles, but since it receives the outflow from Loch Mhic' 
Ille Riabhaich its total drainage area is nearly 4 square miles an area 
eight times greater than that of the loch. The volume of water is 
estimated at 486 million cubic feet, and the mean depth at 34 feet. The 
bottom in the south-western part of the loch is rather irregular, while 
the north-eastern part forms a simple deep basin, the maximum depth 
of 143 feet having been observed near the centre at the widest part of 
this portion. Section A-B is taken across this wide portion at the 
position of the deepest sounding. The areas between the consecutive 
contour-lines, and the percentages to the total area, are as follows: 

to 25 feet 184 acres 56'2 per cent. 

25 ,, 50 ,, 84 ,, 25-5 

50,, 75 17 ,, 5-3 

75,, 100 17 5-0 

Over 100 ,, 26 8*0 

328 . 100-0 



THE FRESH- WATER LOCHS OF SCOTLAND. 229 

These figures indicate that the average slope is gentle in the 
shallower water, and much steeper in depths exceeding 50 feet, but 
it will be observed from the map that the contour-lines approach 
very close to the shores in certain places, indicating a steep slope in 
these positions. 

Temperature Observations. The surface temperature at 11.45 a.m. 
on July 29, 1902, was 56'l, and at 4 p.m. on July 30, when the 
following series was taken, it was more than half a degree lower : 

Surface ... ... ... ... ... ... ... 55 '4 Fahr. 

10 feet 55'4 

20 55'4 

30 ~ 55'4 

50 53'6 

7-1 49-8 

85 , 48'4 

120 ... 47'2 

This series shows a constant temperature from the surface down to 
30 feet, then a slight fall of l-8 between 30 and 50 feet, followed by a 
rapid fall of 5-2 between 50 and 85 feet, thence to the bottom a slight 
fall of 1 0< 2, the total range of temperature from surface to bottom 
being 8-2. 

Loch Mhic' Ille Riabhaich (see Plate L.). Loch Mhic' Ille Riabhaich 
is a small, irregular, shallow loch lying to the south-east of Loch a' 
Bhaid-Luachraich (into which it flows by the Allt na Criche), surrounded 
by low, rounded hills ; 011 one of the islands is a fortress, but nothing 
seems to be known of its history. It was surveyed on July 31, 1902, 
but its elevation above the sea could not be determined; from the 
contour-lines on the Ordnance Survey maps it is apparently rather 
less than 600 feet above the sea. It is half a mile in length from 
north to south, and rather less in maximum breadth from south-east to 
north-west. It covers an area of about 36 acres, and drains an area of 
nearly three-quarters of a square mile. Two soundings of 12 feet were 
taken near the north end at the outflow, and a sounding of 10 feet off 
the eastern shore of the larger island ; with these exceptions, the lake- 
floor is covered by less than 10 feet of water. The volume is estimated 
at 8 million cubic feet, and the mean depth at 5J feet. 

The temperature of the surface water at 12.30 p.m. on July 31, 
1902, was 57-0 Fahr. 

Loch nan Dailthean (or na Daline), lying to the south-west of Loch 
Mhic' Ille Riabhaich, and flowing into Loch Thuirnaig (an inlet of 
Loch Ewe), was visited by the Lake Survey, but not sounded. It is 
said to be so shallow that cows may walk over the whole of it, except 
a small hole near Thuirnaig House, in which the depth is 4 feet. 



230 BATHYMETRICAL .SURVEY OF 

Loch an t-Slagain (see Plate L.). Loch an t-Slagain lies to the east 
of Slaggan bay, at the entrance to Loch Ewe, into which it flows by 
the Allt an t-Slagain. It is surrounded by low hills, and receives the 
outflow from several small lochs lying to the east and south. It 
was surveyed on August 11, 1902; the elevation above the sea was 
determined by levelling to be 103-5 feet; when visited by the officers 
of the Ordnance Survey on May 5, 1875, its elevation was 102*6 feet 
above sea-level. The height of the highest drift-mark observed was 
2-3 feet above the surface of the water on August 11, 1902, so that the 
range of level is probably between 3 and 4 feet. The loch trends in a 
north-west and south-east direction, and is two-thirds of a mile in 
length by one-third of a mile in maximum breadth. Its waters cover 
an area of about 77 acres, and it drains an area 17 times greater, or 
over 2 square miles. The maximum depth of 55 feet was observed 
comparatively very near the south-eastern shore. The volume of water 
is estimated at 55 million cubic feet, and the mean depth at 16| feet. 

Loch an t-Slagain is of simple conformation, the 10-feet area being 
continuous from end to end, but the deeper water is cut into two 
portions by the shallower water around the central islands. To the 
north-west of the islands two soundings of 25 feet were recorded, 
while the deepest part of the loch lies to the south-east of the islands. 
The areas between the consecutive contour-lines, and the percentages 
to the total area, are as follows : 

to 10 feet 27 acres 35 '3 per cent. 

10,, 25 39 50-6 

25,, 50 8 10-6 

Over 50 , 3 , 3'5 



77 ,, 100-0 



Thus 86 per cent, of the lake-floor is covered by less than 25 feet of 
water, and the major portion is covered by water between 10 and 25 
feet in depth. 

Loch Sguod (see Plate L.). Loch Sguod lies less than half a mile 
from the western shore of Loch Ewe (opposite the Isle of Ewe), into 
which it flows by the Uidh Chro. It drains the higher ground to the 
west and south-west by several streams flowing through the low peat 
bogs which surround the loch on all sides. It was surveyed on August 
15, 1902, but its elevation above the sea could not be determined; the 
water may rise 2 feet above its level on the date mentioned. Loch 
Sguod is nearly three-quarters of a mile in length, with a maximum 
breadth of nearly half a mile, the mean breadth being a quarter of a 
mile. Its waters cover an area of about 107 acres, and it drains an 
area 26 times greater, or 4J square miles. The maximum depth of 



THE FRESH- WATER LOCHS OF SCOTLAND. 231 

14 feet was recorded towards the eastern shore. The volume of water 
is estimated at 32 million cubic feet, and the mean depth at 7 feet, or 
half the maximum depth. The loch is quite simple in conformation, 
but the deeper water is confined to the central and north-eastern parts 
of the loch, approaching very close to the eastern shore, off which the 
slope is steep. The area of the lake-floor covered by less than 10 feet 
of water is about 78 acres, or 73 per cent, of the total area. The 
temperature of the surface water at 9 a.m. on August 15, 1902, was 
57-2 Fahr. 

Loch an Drainc (see Plate L.). Loch an Drainc (or an Druing) lies 
to the north-west of Loch Sguod, and flows through Loch nan Eun 
(which was not sounded) and the Abhuinn Leumnach into The Minch, 
about 2J miles to the west of the entrance to Loch Ewe. The ground 
around the loch is mostly covered with peat, and to the east are low 
but -steep knolls 200 to 300 feet in height, dotted over with small and 
beautiful lochs, while to the west and south there is a fairly steep 
ascent to Maol Breac, An Cuaidh, and Bac an Lethchoin (over 900 
feet), the sides of which are well wooded. It was surveyed on August 
16, 1902, but the elevation above the sea could not be determined; 
the water may rise 2 to 3 feet above its level on this date. Loch an 
Drainc trends north-north-west and south-south-east, and is nearly 
three-quarters of a mile in length, with a maximum breadth of over 
one-third of a mile, the mean breadth being nearly a quarter of a mile. 
Its waters cover an area of about 96 acres, and it drains an area 22 
times greater, or nearly 3J square miles. The maximum depth of 55 
feet is approximately centrally placed, but nearer the western than the 
eastern shore. The volume of water is estimated at 108 million cubic 
feet, and the mean depth at 26 feet, or nearly half the maximum 
depth. The loch forms a simple basin, and, considering its area, is 
comparatively deep, the 25-feet area being over half a mile, and the 
50-feet area one-fifth of a mile, in length. The areas between the 
consecutive contour-lines, and the percentages to the total area, are 
as follows : 

to 25 feet 47 acres 48 '9 per cent, 

25,, 50 45 47-2 

Over 50 , 4 , 3'9 



96 , 100-0 



Temperatures taken at 3 p.m. on August 16, 1902, gave 59 0> at 
the surface, and 58*0 at a depth of 40 feet. 

Deposits. The deposits from certain parts of Loch an Drainc, as 
well as of Loch Sguod, were of a strikingly pink colour, and a sample 
from a depth of 20 feet in Loch an Drainc was found to be coherent 



232 









- 



EATHYMETRICAL SURVEY OF 

Tt< O tp ip CO 7^ . 



11 



squ 
mil 



.S 
8S 

4<sfs 



111 

> .SS 



II 

03 



85 



1 



2^^ ' 
JSS.1 



3 s 



l!.s 




W.2 



or^i iast-~osci>"- < r^ -* t^ cc 
oo co * cc p p o QO 95 cp p * * 



6^6666666 



CC ZO QC i^T ^ OC 

^X 1 CCCO 



1_ * !_; ; ; _J _ V_. ^r _L Ij; 5i^ ^rr *_. 
'^O vQ Oj 1^* t^* OC TP ^ w* ~T 00 O O "^ 

IO l-H, li-HCCi-H^HCC'MTtHOaiO- I 



^ 



o o 

3 '3 



o p i 
So 



T3 o 

M 
gh^ 

^ 

^ 

S^J 



II 

o'" 



THE FRESH- WATER LOCHS OF SCOTLAND. 233 

when dry, and when wet plastic and creamy, not unlike cocoa and milk 
of a pink brown colour. The material is made up of probably 90 per 
cent, of clayey matter with minute mineral particles less than O05 mm. 
in diameter, the remaining 10 per cent, consisting of mineral particles 
with a mean diameter of 0'15 mm. Quartz is the principal mineral 
species, but small grains of pink microcline-felspar are very abundant, 
and it is apparently to this mineral that the pink colour of the deposit 
is due; the microcline shows cross-hatching, and is much kaolinized. 
The washed mineral grains have a decided pink tinge, which is, how- 
ever, much more pronounced in the fine washings. Besides quartz and 
felspar, white and brown mica, hornblende, garnet, and magnetite were 
observed. There is little or no vegetable matter. 

The particulars regarding the lochs in this basin are collected 
together in the table on p. 232 for convenience of reference and com- 
parison. From this table it will be seen that in the fourteen lochs under 
consideration, which cover an area of nearly 15 square miles, nearly 
2500 soundings were taken, or an average of 167 soundings per square 
mile of surface. The aggregate volume of water contained in the lochs 
is estimated at 44,500 millions of cubic feet, and the area draining 
into them is 185J square miles, or 12J times the area of the lochs. 



NOTES ON THE GEOLOGY OF THE LOCH MAREE DISTRICT. 

By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. With 
Geological Map (Plate LI.). Published by permission of the 
Director of the Geological Survey. 

The Loch Maree district presents features of special geological 
importance relating to the subdivisions of the Archaean rocks, to the 
topography of the old pre-Torridoniaii land surface, and to the series 
of terrestrial movements which affected the north-west Highlands in 
post-Cambrian time. Throughout the mountainous region, stretching 
north to Dundonnell forest and south to Achnashellach and Glen 
Shieldaig, excellent sections are to be found showing the geological 
structure of that region. 

The Archaean rocks (gi on map), lying to the west of the great post- 
Cambrian displacements, occur mainly in the north-west of the area, 
where they form a broad tract of mountainous ground between Loch 
na Sheallag and Loch Maree, and westwards by Torrisdale to Gairloch. 
There is also an important development of them on both sides of Loch 
Torridon above Loch Shieldaig, and they likewise appear as inliers, 
surrounded by Torridon Sandstone, as, for instance, on the southern 
slope of Beinn Dearg north of Liathach. Within the territory affected 



234 BATHYMETRICAL SURVEY OF 

by the post-Cambrian movements there are masses of displaced 
gneiss, of which the most important lies immediately to the north 
of Kiiilochewe; others appear further north on Mullach Coire Mhic 
Fhearchair, and far to the south on Glas Bheinn, on Torr na h-Iolaire, 
and at Coulags in Glen Carron. Over much of the region they form 
lofty ground and give rise to prominent peaks, as, for example, Beinn 
Lair (2817 feet), Beinn a' Chaisgein Mor (2802 feet), and Beinn Airidh 
Charr (2593 feet), all north of Loch Maree. 

Throughout this area there is a remarkable development of those 
types of Archaean rocks that have affinities with plutonic igneous 
products, consisting mainly of massive and foliated, pyroxenic, horn- 
blendic, and micaceous gneisses. Along the northern margin of this 
district, between Loch na Sheallag and Gruinard Bay, the original 
characters of the rocks that enter into the fundamental complex are 
well displayed. The various stages in the separation of the ferro- 
magnesian from the quartzo-felspathic constituents, and the gradual 
development of mineral banding in the massive gneisses are there clearly 
shown. In that area, also, the intrusive character of the basic dykes 
traversing the gneiss in a west-north-west direction is proved beyond all 
doubt. Passing southwards to the tract lying south of Poolewe, both 
the gneisses and the intrusive dykes have been thrown into an anticlinal 
fold, which is represented on the Geological Survey Map (Sheet 91). 
Here we find that, under the influence of mechanical stresses, there 
has been differential movement of the rock constituents, and linear 
foliation has been developed in the basic dykes the foliation being 
parallel with the pitch of the folds. Further south in the Torridon 
district biotite gneisses prevail, which are traversed by bands of horn- 
blende-schist representing the original basic dykes. 

Of special interest is the development of crystalline schists, that 
have affinities with rocks of sedimentary origin, north of Loch Maree 
and near Gairloch. The prominent members of this series are quartz- 
schists, mica-schists, graphitic-schists, limestones, and dolomites, with 
tremolite, garnet, and epidote, which are there associated with a massive 
intrusive sheet of hornblende-schist. Lithologically some of these 
crystalline schists closely resemble the altered sediments in the Eastern 
Highlands. The quartz-schists, mica-schists, and limestones are well 
exposed in various folds between Letterewe and Glen Tulacha, west of 
Lochan Fada, pierced by the great sill of hornblende-schist forming 
Beinn Lair and Beinn Airidh Charr (B G on map). The original 
relations of these altered sediments to the gneisses that have affinities 
with plutonic igneous rocks have been obscured by subsequent earth 
stresses. But along their outer margin they are bounded by gneiss 
apparently underlying them, and they are visibly overlain by gneiss 
with basic dykes, the whole series being affected by a common system of 
folds. 



THE FRE8H- WATER LOCHS OF SCOTLAND. 235 

One of the most remarkable geological features of the Loch Maree 
district is the evidence relating to the topography of the primeval land 
surface on which the Torridoniaii sediments were laid down. Between 
the head of Loch Maree and Strath na Sheallag, where the overlying red 
sandstone has been partly removed by denudation, it is possible to trace 
the direction of the old valleys and the orientation of the ancient 
peaks. On the eastern slope of Ben Slioch, near Glen Fh'asaigh, the 
observer may climb one of these hills, which rises to a height of 
about 2000 feet in the midst of the Torridon Sandstone, and trace the 
alternation of breccia and sandstone filling the ancient valley. Similar 
evidence is obtained further north in the mountainous region near the 
head of Glen na Muic. Where these deeply-eroded valleys are pre- 
served, breccias of local origin frequently appear at the base of the 
Torridon Sandstone. In the Loch Maree district this formation has 
been subdivided into three groups : a lower, consisting of epidotic grits, 
dark and grey shales, with calcareous bands and red sandstones; a 
middle, composed of a great thickness of false-bedded grits and sand- 
stones with scattered pebbles ; an upper, comprising chocolate-coloured 
sandstones, micaceous flags, with dark shales and calcareous bands. 
The members of the lower group are well displayed in the district near 
Talladale and Slattadale, on the south-west shore of Loch Maree ; those 
of the middle group are typically developed in the mountains round 
Loch Torridon, from which district this system takes its name, while 
the upper group appears in the islands north of Gruinard. Throughout 
this region this formation (t on map) reaches a vast thickness, for on 
the shores of Loch Torridon it rises on Liathach from the sea-level to 
a height of over 3000 feet. In the mountains between Slioch and An 
Teallach these sandstones have a gentle dip towards the south-east; 
in the Torridon district they are nearly horizontal, while further south 
they form a low arch. 

As indicated in our previous notes on the geology of the Assynt 
district, the Torridon Sandstone is separated from the overlying 
quartzites by an unconformability, which in some parts of the Loch 
Maree area is not so prominent as in Assynt. On An Teallach in 
the Dundomiell forest and southwards towards Mullach Coire Mhic 
Fhearchair, the Cambrian quartzites are inclined at a higher angle 
to the south-east than the Torridon Sandstone. In the area lying to 
the west of the post-Cambrian displacements we find at various localities 
the normal Cambrian sequence in ascending order 1, the basal 
quartzites (a 1 on map); 2, the pipe-rock (a 2 ); 3, the Fucoid beds (a 3 ). 
This sequence is displayed in the Dundonnell forest, on the western 
slope of Ben a' Vuinie near Kinlochewe, on the west declivity of Meall 
a' Ghuibhais south of Loch Maree, and on Beinn Eighe. Within these 
limits the Fucoid beds have yielded at several localities well-preserved 
trilobites and other organic remains of Lower Cambrian age. The 



236 BATHYMETRICAL SURVEY OF 

Cambrian limestone rarely appears in the undisturbed area; in the 
displaced masses west of Glas Bheinn towards the head of Loch Kishorn 
it is largely represented. 

The evidence bearing on the .post-Cambrian movements obtained in 
the Loch Maree district is of special interest. On referring to the 
map, it will be seen that the belt affected by these movements runs 
southwards from Dundonnell by Kinlochewe, Beinn Eighe, and the 
Coulin forest to Glen Carron and Loch Kishorn. Throughout this 
area the geological structure is extremely complicated, but certain 
sections may be referred to as illustrating the continual variation in 
the relations of the rocks. The simplest type is met with in the 
Dundonnell forest, where on the west slope of Creag Rainich there are 
two powerful thrusts running parallel with each other for some distance 
in a north-north-east and south-south-west direction. West of these 
lines of displacement the Cambrian sequence is undisturbed from the 
basal quartzites to the Fucoid beds. On the horizon of the latter the 
first powerful thrust is met with, which brings forward a slice of 
Torridon Sandstone with a core of Archaean gneiss. Not far to the east 
the second thrust supervenes, which ushers in the crystalline schists 
overlying the Moine thrust-plane. A repetition of this structure in a 
more complicated form is found in the tract between Glen Fhasaigh 
and the heights of Kinlochewe, where the mass of displaced gneiss 
with its intrusive dykes is admirably displayed between the Moine 
thrust to the east and the outcrop of the Kishorn and Kinlochewe 
thrust-plane west of Ben a' Vuinie. 

In the region stretching south from the head of Loch Maree by 
Beinn Eighe and the Coulin and Achnashellach forests to Loch Kishorn 
the structure is more complicated. For to the west of the two great 
lines of displacement just referred to, which have been traced south to 
Loch Kishorn and Glen Carron, the Torridon Sandstone and Cambrian 
strata have been repeated by a series of inverted folds and minor 
thrusts. Hence we find strips of Cambrian quartzite alternating with 
Torridon Sandstone, the strata having a general dip towards the south- 
east as if they formed part of a normal ascending sequence. The clear 
sections, however, on Beinn Eighe, on Sgurr Dubh, Beinn Liath Mhor, 
Sgurr Ruadh, and other peaks, show the overfolding and reversed 
faults which are the prominent features of the structure of that region. 
Still further south, towards the head of Loch Kishorn, and west of the 
slice of Archaean gneiss overlying the Kishorn thrust-plane, there is a 
constant repetition of the Fucoid beds and Cambrian limestone by 
inverted folds and reversed faults. 

In the Loch Maree district, as in Assynt, there is evidence of 
the development of new structures resulting from the post-Cambrian 
movements. The deformation of the Torridon Sandstone, west of the 
Moine thrust, is well displayed in the stream south of the Kinlochewe 



THE FRESH- WATER LOCHS OF SCOTLAND. 237 

Hotel, where the grits have been made schistose, and where the felspars 
have been partially broken down and reconstructed. Near the outcrop 
of the Kishorn thrust, west of Glen Carron, the Lewisian gneiss is 
sheared and rolled out, passing into flaser gneiss and schist with a 
platy or fluxion structure. 

East of the Moine thrust, which runs south from Dundonnell by 
Loch an Nid, the heights of Kinlochewe, and Loch Coulin to Glen 
Carron, the area represented on the map is occupied by crystalline 
schists of a remarkably uniform type. They consist mainly of flaggy 
granulitic quartzose schists and mica-schists, with prominent belts of 
garnetiferous muscovite-biotite schists. The latter are well developed 
on Fionn Bheinn, north of Achnasheen, and on Sgurr Mor Fannich, 
where they form conspicuous crags. Near the Moine thrust, and, 
indeed, for some miles to the east of the plane of that thrust, the 
Eastern or Moine schists have a persistent dip to the south-east. In 
the Fannich mountains they are over-folded on a stupendous scale, 
and similar evidence is obtained in the group of mountains north of 
Achnasheen. 

Reference must now be made to the faults that affected the area after 
the post-Cambrian thrusts. Of these by far the most important is the 
great line of displacement that crosses the region in a north-west and 
south-east direction, coinciding with the long axis of Loch Maree, 
which may be termed the Loch Maree fault. It has been traced in a 
north-west direction along the river Ewe, by the south margin of Loch 
Ewe, towards Loch an Drainc, where the Torridon Sandstone on the 
north-east side is faulted down against the Lewisiau gneiss at Poolewe. 
At Kinlochewe this dislocation has been traced up Glen Dochartie and 
onwards in the direction of Ledgowu. Indeed, the probable con- 
tinuation of this fault has been recently found far to the south-east in 
the basin of the Conon. Where the line of fault is not obscured by 
drift, it gives rise to a prominent feature on the surface of the ground. 
This powerful fault shifts the outcrops of the Moine and Kishorn 
thrust-planes, and likewise of the overfolded strata associated with 
these thrusts. It further shifts the outcrop of the normal fault in 
Glen Fhasaigh, which runs in a north-east direction between the head 
of Loch Maree and Lochan Fada (see map). The continuation of the 
Fhasaigh fault is to be found in Glen Grudie, on the south side of Loch 
Maree, so that its outcrop is shifted at least for a distance of two miles 
by the Loch Maree dislocation. 

In the north-west part of the area, in Isle Ewe, and in the pro- 
montory between Loch Ewe and Gruinard Bay, there is a strip of 
Triassic Sandstone (/ on map) thrown down by two powerful faults. 

Throughout the Loch Maree district, and especially in the moun- 
tainous region embracing the Torridon Sandstone and the Cambrian 
quartzite, there is evidence of intense glaciation. During the climax 



238 BATHYMETRICAL SURVEY OF 

of the glacial period, even the highest mountains in the Loch Maree 
district were overridden by the ice. Some of the evidence pointing to 
this conclusion may here be referred to. Along the top of Ben Slioch 
(3217 feet), which, as already indicated, is composed of Torridon Sand- 
stone, blocks of thrust Archaean gneiss, Cambrian quartzite, and 
Moine schists are met with, all of which have been derived from the 
east. Similar evidence is obtained on Meall Ghuibhais (2882 feet), on 
the south side of Loch Maree. Again, in the Coulin forest, on the lofty 
ridge running south from Sgurr Dubh (2566 feet) to Beinn Liath Mhor 
(3034 feet), striae have been recorded pointing in a westerly direction at 
elevations ranging from 1750 to 2000 feet. Blocks of crystalline schist 
derived from the area east of the Moine thrust, and occasional frag- 
ments of thrust Archaean gneiss, appear on this ridge. Further south 
on Sgurr Ruadh, ice-markings pointing a few degrees to the north of 
west occur at an elevation of 2500 feet. The top of Ruadh Stac (2919 
feet), on the east side of Glen Kishorn, is finely glaciated, the striae 
pointing W. 25 N. The summit of Meall a' Chinn Dearg (3095 feet), 
composed chiefly of Torridon Sandstones and grits, is strewn with 
transported blocks of Cambrian quartzite. Similar evidence might be 
adduced regarding that part of the Applecross area which is shown in 
the south-west corner of the map. For there, on Beinn Bhan (2936 
feet), striae have been recorded underneath the 2750 feet contour-line 
trending W. 13 to 20 N. Blocks of the Eastern or Moine schists 
appear at that level, and are fairly plentiful below 2500 feet. From 
these facts the inference seems obvious that during the maximum 
glaciation the western part of Ross-shire must have been completely 
overridden by ice moving in a westerly direction towards the sea. 

The westerly flow of the ice is confirmed by the transport of the 
boulders in the drift deposits, which consist mainly of moraines in the 
area lying to the west of the Moine schists, and these contain numerous 
blocks of quartzose-schist and mica-schist derived from the east. 

After the disappearance of the great ice-sheet there ensued a period 
of confluent valley glaciers. The direction of the ice-flow during this 
later glaciation is represented on the map by feathered arrows. On 
referring to the map, it will be seen that the prominent mountain 
groups north and south of Loch Maree formed independent centres of 
glaciation. In many of the valleys there is a splendid development of 
both lateral and terminal moraines. The closing phases of the glaciation 
of the region are indicated by the moraines encircling some of the high 
corries, and by similar deposits resting on the 50-feet beach at the head 
of Loch Torridon, where they have been recorded by our colleague, 
Mr. Hinxman. 

A glance at the map will show that Loch Maree is by far the largest 
rock basin in that district ; but as it lies along the line of a powerful 
fault, which has given rise to a prominent feature in the topography 



THE FRESH-WATER LOCHS OF SCOTLAND. 239 

of the region, we prefer not to discuss its features in connection with 
the theory of the glacial origin of lake basins. 

Loclian Fada is a simple rock basin resting partly on Torridon 
Sandstone and partly on Lewisian gneiss. Along the greater part of 
its course it coincides with an old pre-Torridonian valley, trending in a 
west-north-west direction. At its eastern end it is bounded by the 
continuation of the Glen Fhasaigh fault, which brings down the 
Cambrian quartzite, Fucoid beds, Serpulite grit, limestone, and over- 
lying Archaean gneiss above the Glen Logan or Kishorn thrust-plane. 
The sudden deepening of the loch at its lower end is evidently related 
to this fault, because harder and more durable strata on the east side 
of this fault have been brought against the softer Torridon Sandstone 
to the west. It is important to note that the downthrow side of this 
fault is towards the east ; in other words, the eastern floor of Lochan 
Fada is not faulted down to the west. It is interesting to note that the 
deepest part of the basin, and the deepest sounding (248 feet), lie 
between Slioch and Ben Tarsuinn, where the erosion of the ice during 
the maximum glaciation would probably be greatest. 

Loch Garbhaig, which is situated to the north of Ben Slioch, is a 
small lake over a mile in length, and evidently a rock basin from the 
appearance of Lewisian gneiss at its exit, where it is drained by the 
Amhainn na Fuirneis. The soundings prove the existence of two 
basins separated by a ridge, the eastern one reaching a depth of 93 feet, 
and the western 50 feet close to its outlet. This lake lies mainly along 
the junction of the Archaean rocks and Torridon Sandstone, the older 
rocks forming the greater part of the north shore, and the red sand- 
stone the larger part of the south margin. A tongue of Torridon 
breccia occupies a hollow in the Archaean rocks on the north shore, 
where it rests on a mass of hornblende-schist. This breccia appears in 
an island in the loch, which forms part of the ridge separating the two 
basins. The loch may therefore be regarded as a rock basin eroded by 
ice, mainly out of Torridon Sandstone along its line of junction with 
the Archaean floor. 

Loch Kernsary is very irregular in shape, and has four basins below 
the 50-feet level, the deepest sounding 93 feet being found near its 
north-west extremity. The Archaean gneiss forms part of its north-east 
shore, while the Torridonian rocks floor the remaining portions, save 
near the west limit of the north shore, where a boss of Lewisian gneiss 
projects through the Torridon Sandstone. As the Torridon sandstones 
and conglomerates dip at angles varying from 20 to 35 to the north- 
west, we may infer that those sediments are resting on a very uneven 
floor of gneiss. The bed of the lake, therefore, may here correspond 
with the pre-Torridonian surface, the softer Torridon Sandstone being 
more easily removed than the more durable gneiss. Striae pointing in 
a north-west direction are found round the lake, the trend of which is 



240 BATHYMETRICAL SURVEY OF 

slightly oblique to the long axis of the loch, but almost parallel to 
that of the 50-feet basins. The latter in turn have their longer axes 
somewhat oblique to the strike of the Torridonian strata. 

Loch Ghiuragarstidh is a shallow loch lying along the strike of the 
Torridon Sandstone, with an exposure of Lewisian gneiss near its outlet, 
its greatest depth being 37 feet. A long ridge of sand and gravel, 
probably a moraine, occurs near its mouth, so that this lake may lie 
partly in drift and partly in rock. 

Loch Tollie is a true rock basin of very irregular shape, surrounded 
by Lewisian gneiss, the deepest sounding being 86 feet. This basin 
belongs to the shallow plateau type so common in the Archaean area 
in the west of Sutherland. Its irregularity is due to the folding and 
intense shearing of the component members of the Lewisian gneiss in 
that region. Glacial striae are met with at several localities round the 
loch, varying in direction from W. 10 N. to W. 41 N. The dominant 
strike of the foliation of the gneiss is west-north-west and east-south- 
east. The long axes of the bays in the loch are more in accordance 
with the direction of the ice-flow than with the strike of the foliation. 

Loch Glair lies partly in moraine drift and partly in thrust 
Torridonian strata. Drift occurs at the outlet and along its western 
margin, and all the islands are composed of moraines. 

Loch Coulin is separated from Loch Clair by an alluvial fan brought 
down by the Allt na Luib. The river Coulin has silted up the greater 
part of the upper end of the lake, and its limits have been still further 
restricted by detritus borne downwards by the streams on the north. 



THE FRESH- WATER LOCHS OF SCOTLAND. 241 






LOCHS OF THE SHIEL BASIN. 

ONLY two lochs belonging to this basin were sounded, viz., Lochs Shiel 
and Dilate ; one or two other small lochs within the basin (the principal 
one being Lochan Dubh, at the head of Glen Hurich) were not sounded. 

Loch Shiel (see Plates LII. and LIIL). Loch Shiel is one of the 
larger Scottish fresh-water lochs, having a total length of 17^ miles. In 
this respect it is inferior only to Lochs Awe, Ness, and Lomond, which 
are 25J, 24^, and 22 J miles in length respectively, and is closely followed 
by Loch Shin, which is 17^ miles in length. Its elevation above the sea 
is only 11 J feet, so that a slight subsidence of the strip of land through 
which the river Shiel flows would convert it into an arm of the sea. 
Seals occasionally make their way into this loch from the sea at the 
present time. The principal upper portion of the loch trends in a 
north-east and south-west direction, but about 6 miles above the outflow 
there is a bend in the outline of the loch, and the lower portion trends 
almost due west. The river Shiel follows a north-westerly course for 
about 2 miles before emptying itself into Loch Moidart. The scenery 
around the loch is very fine, becoming grand and wild towards the 
head. At the foot of the loch the surrounding ground is low, but on 
proceeding up the loch mountainous country borders the loch on both 
sides, culminating in heights exceeding 3000 feet at the head of Glen 
Finnan. To 'the south rises Ben Resipol (2774 feet), between Loch 
Shiel and Loch Sunart; to the east Sgor an Tarinachain (2474 feet), 
Meall Mor (2487 feet), Meall nan Creag Leac (2474 feet), Glas Garbh 
(2369 feet), Meall Doire na Mnatha (2094 feet); to the north Beinn 
nan Tom (2603 feet), Streap (2988 feet), Sgor Choileam (3164 feet), 
Sgor nan Coireachan (3133 feet), Fraoch-bheinn (2489 feet); to the 
west Beinn Odhar (2895 feet), Druim Fiaclach (2851 feet), a' Chroit- 
bheinn (2178 feet), and Beinn Gaire (2179 feet). The principal feeders 
are the river Finnan, Amhainn Shlatach, and Gallop river, which enter 
the loch at its head, Glenaladale river entering about 6 miles down on 
the north-western shore, and the river Polloch (bearing the outflow 
from Loch Dilate) entering about 11 miles down on the south-eastern 
shore, where the bend in the trend of the loch occurs. There are 



242 BATHYMETRICAL SURVEY OF 

numerous small islands and a few larger ones, the largest being Eilean 
Gleann Fhionainn at the head of the loch, while on Eilean Fhiaiiain, 
at the narrows towards the foot of the loch, are the remains of St. 
Finnan's Church and a romantic burying-place of the Clanranald. At 
the head of the loch stands Prince Charlie's monument, erected by the 
late Colonel Macdonald, of Glenaladale, on the spot where that ill-fated 
prince raised his standard. Salmon, grilse, sea-trout, and brown trout 
abound in the loch, and yield fair sport, some of the salmon and trout 
being very heavy. 

Considering its great length, Loch Shiel is very narrow, for at no 
place does the loch attain a width of a mile, the maximum breadth 
being about nine-tenths of a mile, and this occurs at the great bend in 
the outline of the loch, opposite the entrance of the river Polloch. The 
mean breadth of the loch is less than half a mile, being only 2| per cent, 
of the length a smaller percentage than has been observed in any of 
the larger lochs surveyed by the Lake Survey, the lochs most nearly 
approaching it in this respect being Loch Shin with 3 per cent., and 
Loch Ness with 4*3 per cent. The waters of Loch Shiel cover an area 
of about 4840 acres, or over 7J square miles, and it drains directly an 
area of over 72 J square miles, but, since it receives the outflow from 
Loch Dilate, its total drainage area is about 85J square miles an area 
over eleven times greater than that of the loch. Over 700 soundings 
were taken, the maximum depth recorded being 420 feet, about 4 miles 
from the head of the loch, between the heights of Beinn a' Chaoruinn 
and Beinn Odhar Bheag to the north-west, and of Meall nan Creag 
Leac to the south-east. The volume of water contained in the loch is 
estimated at 27,986 million cubic feet, and the mean depth at 132| 
feet, or nearly 32 per cent, of the maximum depth. Loch Shiel was 
surveyed on July 2 to 9, 1902. The elevation of the lake-surface above 
the sea was determined, by levelling from bench-mark, as being 11 '4 
feet ; when levelled by the officers of the Ordnance Survey on November 
6, 1897, the elevation was found to be 12 feet above sea-level. The 
water may rise 4 to 5 feet higher than the level given above. 

The floor of Loch Shiel is on the whole rather irregular. The 
50-feet contour-line encloses a continuous area extending from close to 
the upper end to within 2 miles from the lower end at Acharacle, but 
all the deeper contours are broken up so as to enclose two or more 
isolated areas. The 50-feet contour follows approximately the general 
outline of the loch, but it is in places of a sinuous character. At the 
head of the loch it extends both to the north-west and south-east of 
Eilean Ghleann Fhionainn. About 2 miles down there are sinuosities 
in the contour on both sides of the loch, due to a tongue of deep water 
projecting between the south-eastern shore and the island Sgeir Ghiubh- 
sachain, and to a shoaling of the water off the north-western shore 
from 33 to 15 feet. Further down, off the north-western shore, above 



THE FRESH- WATER LOCHS OF SCOTLAND. 243 

the entrance of the Glenaladale river, there is a twist in the 50-feet 
contour, where the water shoals from 55 to 20 feet. Still further down, 
opposite the entrance of the Allt na Dalach, sinuosities in the 50-feet 
contour occur on both sides of the loch, the water shoaling off the south- 
eastern shore from 47 to 35 feet, and off the north-western shore from 
41 to 19 and 22 feet. The last-mentioned shoaling occurs to the north- 
east of Eileanan Comhlach, at the entrance of the Allt a' Ghiubhais, 
and it is curious to observe a similar shoaling on the opposite (south- 
west) side of the island from 41 to 18 and 21 feet, while between the 
island and the mouth of the stream a depth of 32 feet was observed. 




FIG. 41. LOCH SHIEL, FROM PRINCE CHARLIE'S MONUMENT. 

(Photograph by Mr. T. A r . Johitrtvit, M.B., C.M., F.R.S.E.) 



Towards the lower end of the wide part of the loch, and almost due 
south of Eilean Druim nan Laogh (or Heron island, as it is now called 
in the district), there is, near the middle of the loch, a shoal covered by 
only 2 or 3 feet of water. During the visit of the Lake Survey the 
regular mail steamer was laid up for repairs, having shortly before 
struck on this shoal and damaged the propeller. The captain of the 
steamer supplied information as to the position of the shoal, and the 
local gillie employed by the surveyors stated that in calm weather the 
bottom can be seen, but in the stormy weather prevailing at the time 
of the survey he was unable to find it, so that it must be of very small 
extent, for deep soundings were recorded near the spot indicated. The 



244 BATHYMETRICAL SURVEY OF 

same gillie stated that a shoal bank extended from Ruadh Bac na Moine 
in an approximately south-west direction towards the opposite shore; 
this was confirmed by fishermen, and is probably indicated by the 
outward bend of the 50-feet contour-line at that place. 

The 100-feet contour-line is less sinuous in character than the 50-feet 
contour, the main basin being about 12 miles in length, extending 
from near the head of the loch to the narrows at Eilean Fhianain, 
with two small subsidiary basins one off Rudha Leathan, about 3J 
miles from the foot of the loch, based on a sounding of 112 feet; 
the other between the promontory on the south-eastern shore called 
Rudha Torr a' Chonnaidh and the outlying islands, about 7 miles from 
the head of the loch, based on a sounding of 148 feet. A remarkable 
rise in the bottom was observed within the main 100-feet basin, about 
a mile above the entrance of the river Polloch, where soundings of 
84 and 43 feet were taken, surrounded on all sides by about 150 feet 
of water. The contour of the lake-floor along this line of soundings is 
shown in cross-section C-D on the map (Plate LII.). 

The main 200-feet basin is nearly 8 miles in length, approaching 
to within half a mile from the head of the loch, and extending as far 
down as Eileanan Comhlach. There are two small subsidiary basins, 
separated from the main basin by an interval of over half a mile, 
between the entrance of the Allt na Claise on the south-eastern shore 
and the entrance of the An Garbh-allt on the north-western shore. 
This line of soundings shows a curious configuration of the bottom, 
which rises in the central part of the loch and sinks again on both sides 
nearer the shore : thus, on proceeding from south-east to north-west the 
water deepens to 201 feet, then shoals to 122 feet, then deepens again to 
172, 209, and 224 feet, shoaling again towards the north-western shore. 
It is interesting to note the close proximity of these two small deep 
basins to the rise covered by 43 feet of water already mentioned. The 
200-feet contour shows a peculiar loop off the north-western shore, 
about 4 miles from the head of the loch, where the water shoals from 
199 to 163 feet. 

The principal 300-feet basin is distant about a mile from the head 
of the loch, and extends down the loch for over 4 miles, enclosing the 
deepest parts of the loch. Separated from this basin by an interval 
of a quarter of a mile (in which the greatest depth is 282 feet) is a 
second small basin based upon a sounding of 307 feet, and after a 
similar interval (in which the greatest depth is 284 feet) there is 
a third 300-feet basin 2 miles in length, having a maximum depth of 
385 feet. Within this third basin there is a slight rise of the bottom 
covered by 288 feet of water; the line of soundings on which this 
rise is situated is shown in cross-section E-F on map (Plate LIIL). 

There are two small basins with depths exceeding 400 feet, the 
smaller about 3 miles from the head of the loch, based on soundings 






THE FRESH- WATER LOCHS OF SCOTLAND. 245 

of 416 and 419 feet, separated by an interval of three-quarters of a 
mile (in which the greatest depth is 375 feet) from the larger, which 
is less than a mile in length and encloses the maximum depth of the 
loch (420 feet), recorded near the north-eastern end of this larger basin, 
and over 4 miles from the head of the loch. The line of soundings, 
which includes the deepest one, is shown on cross-section G-H on map 
(Plate LIIL). 




FIG. 42. LOCH SHIEL, FROM HIGH GROUND AT THE HEAD OF THE LOCH. 

(Photograph by Mr. Darid Brigham.) 

From the foregoing description, it will be noticed that in Loch Shiel 
the deeper water occurs towards the head of the loch. Proceeding from 
Acharacle, at the foot of the loch, one must row 2 miles up before 
encountering a depth of 50 feet ; a further 1 J miles before meeting with 
a depth of 100 feet, and this merely a small patch, a further 1J miles 
having to be traversed before reaching the main 100-feet basin, or a 
total distance of 5 miles from the foot of the loch. The main 200-feet 
basin is distant about 9 miles, the lower 300-feet basin nearly 10 miles, 
and the principal 400-feet basin over 12 miles, from the foot of the 
loch. 



246 



BATHYMETRICAL SURVEY OF 



The areas between the consecutive contour-lines drawn at equal 

intervals, and the percentages to the total area of the loch, are as 
follows : 

2632 acres 54 '4 per cent. 

9G8 ,, 20-0 

711 ,, 14-7 

484 lO'O 

45 <H 



to 100 feet 
UK),, 200 
200,, 300 ,, 
300,, 400 ,, 
Over 400 



4840 



KKVO 



This table shows that more than half of the entire floor of Loch Shiel 
is covered by less than 100 feet of water, and about three-fourths by 
less than 200 feet, while only 1 per cent, is covered by water exceeding 
400 feet in depth. The slope of the bottom is on the whole gentle, but 
in certain places deep water was found comparatively close inshore, 
and the consequent crowding of the contour-lines indicates a steeper 
slope than usual in these positions. 

Temperature Observations. Numerous observations were made on 
the temperature of the surface water of Loch Shiel during the week 
spent on the survey, the range observed being 8'2, from 54 0> 2 to 62 0> 4. 
Three serial temperatures were taken beneath the surface, with the 
following results : 

TABLE OF SERIAL TEMPERATURES TAKEN IN LOCH SHIEL. 



Depth in feet. 


July 5, 1902, 
6p.m. 
Off Scamodale. 


July 8, 1902, 
Off Eilean Druim 
nan Laogh. 


July 9, 1902, 
5 p.m. 
3 miles from head 
of loch. 




Fahr. 


Fahr. 


Fahr. 





57-1 


55-9 


56-5 


5 




54-9 




10 


57-0 


54-5 




20 


56-3 


54-4 


56-5 


30 


55-5 


... 




50 


50-2 


54 : 


56 '-0 


75 


... 


50-9 


... 


100 


47-0 


47-0 


47-4 


130 




46-2 


... 


200 


45-7 




45 : 2 


280 


45-3 






300 


... 


... 


45 : 2 


400 






45-3 



In this table the observations are arranged chronologically, but the 
series given in the first column was taken about midway between the 
other two series, the second column giving a series taken towards 
the foot, and the third column a series taken towards the head, of the 
loch. The central series in the first column was taken three days 
earlier than the others, and is therefore not strictly comparable ; it 
shows a higher temperature in the surface waters, and a lower tempera- 



THE FRKSH- WATER LOCHS OF SCOTLAND. 247 

ture at a depth of 50 feet than in either of the others. The temperature 
observed near the foot of the loch was lower at all depths than that 
observed towards the head, the difference amounting to 2 at 20 and 
at 50 feet, and to 0'4 at 100 feet. The most pronounced fall in 
temperature was recorded between 50 and 100 feet towards the two 
ends of the loch, but between 30 and 50 feet in the central series (first 
column). The range of temperature shown by these serial observations 
is about 12, while the extreme range of all the observations from 
surface to bottom during the week spent on the survey is over 17. 

Loch Dilate (see Plate LIV.). Loch Dilate (or Doilate) lies about 
1J miles to the east of the lower portion of Loch Shiel, into which it 
flows by the river Polloch entering Loch Shiel about 6 miles above 
its outflow. The ground between the two lochs is low, the fall from 
Loch Dilate to Loch Shiel being only 10J feet, but high and moun- 
tainous country surrounds Loch Dilate in all other directions. The 
principal feeder is the river Hurich, which takes its rise in Lochan 
Dubh at the head of Glen Hurich, and after a course of 6 miles empties 
itself into the east end of Loch Dilate. The loch trends east and west, 
and is nearly 1^ miles in length. It is widest towards the east end, 
where the maximum breadth is over one-third of a mile, the mean 
breadth being about one-seventh of a mile. Its waters cover an area 
of about 142 acres, or nearly a quarter of a square mile, and it drains 
an area fifty-eight times greater, or nearly 13 square miles. Forty-five 
soundings were taken in Loch Dilate, the maximum depth observed 
being 55 feet. The volume of water contained in the loch is estimated 
at 145 million cubic feet, and the mean depth at 23J feet, or 43 per 
cent, of the maximum depth. The loch was surveyed on July 8, 1902, 
and the elevation of the lake-surface above the sea, by levelling from 
bench-mark, was found to be 22*0 feet. When levelled by the officers of 
the Ordnance Survey on October 16, 1867, the elevation was found to 
be 23*4 feet above sea-level. 

Loch Dilate forms a simple basin, the deeper water being centrally 
placed, and the contour-lines following approximately the outline 
of the loch. A sounding of 12 feet was recorded off the bay in the 
south-east corner of the loch, apparently surrounded by shallower 
water, though possibly continuous with the 10-feet area, but this is 
the only irregularity in the lake-floor indicated by the soundings. 
Along the central portion of the southern shore the contour-lines 
closely hug the shore, indicating a comparatively steep slope in this 
locality. A section along the central line of the loch from west to 
east is shown in section A-B on the map. The areas between the 
contour-lines drawn in at equal intervals, and the percentages to 
the total area of the loch, are as follows : 



248 BATHYMETRICAL SURVEY OF 

to 25 feet 78 acres 55*4 per cent. 

25,, 50 49 34-3 

Over 50 , 15 . 10'3 



142 , 1000 



Temperature Observations. The following serial temperatures were 
taken at 3 p.m. on July 8, 1902, in the deepest part of Loch Dilate : 

Surface 62 '3 Fahr. 

10 feet ... 62-3 

20 62-3 

25 6l-5 ,, 

30 55 -3 

50 ... 53-3 

This series shows a constant temperature from the surface down 
to a depth of 20 feet, a slight fall of 0-8 between 20 and 25 feet, then 
a very rapid fall of 6 0> 2 between 25 and 30 feet (a fall exceeding 1 per 
foot of depth), and a further fall of 2 between 30 and 50 feet, the 
extreme range of temperature being 9 Fahr. 



THE FRESH- WATER LOCHS OF SCOTLAND. 249 






LOCHS OF THE AILORT BASIN. 

LOCH EILT is the only loch to be dealt with here ; the few very small 
hill lochs within the basin were not surveyed. 

Loch Eilt (see Plate LV.). Loch Eilt lies about 1J miles to the east 
of the head of Loch Ailort (into which its outflow is carried by the 
river Ailort), and about 4 miles to the west of Glenfinnan. The hills 
around it rise steeply up to a height of over 1500 feet, the highest 
points exceeding 2000 feet. It was formerly considered a good loch 
for salmon and sea-trout; but Mr. Harvie-Brown believes that the 
blasting operations during the construction of the Mallaig extension of 
the West Highland railway resulted in the destruction of a large 
amount of spawn and fry, and that now the fish are greatly disturbed 
by the passage of the trains across the bays on the south shore. 

Loch Eilt trends east and west, and is 3J miles in length, with a 
maximum breadth of half a mile, the mean breadth being one-fifth of 
a mile. Its waters cover an area of about 424 acres, or two-thirds of 
a square mile, and it drains an area of 12 square miles. Over 250 
soundings were taken, the maximum depth recorded being 119 feet. 
The volume of water contained in the loch is estimated at 686 million 
cubic feet, and the mean depth at 37 feet. The loch was surveyed on 
July 9 and 10, 1902; the elevation of the lake-surface was found, by 
levelling from bench-marks, to be 96-4 feet above the sea. The keeper 
stated that the water might rise about 3 feet above, and fall about 
9 inches below, this level. During the night of July 9 and 10, 1902, 
the water rose nearly 10 inches. 

Loch Eilt is naturally divided into three portions by two narrow 
constrictions in its outline, the western portion being by far the largest 
and deepest, covering an area of about 360 acres, while the area of the 
central and eastern portions is in each case about 32 acres. The 
western portion is connected with the central portion by a channel 
6 feet in depth, with a rocky islet in the centre, the sides of the 
channel being also of rock in situ, thus dividing the loch into two 
rock-basins ; the central portion is separated from the eastern portion 
by detritus brought down by the Allt a' Choire Bhuidhe, the channel 



250 BATHYMETRICAL SURVEY OF 

between them having a depth of 7 feet. The small eastern and central 
basins are quite simple in conformation, the maximum depth observed 
in the eastern one being 52 feet, and in the central one 70 feet. The 
floor of the large western basin is much more irregular, there being 
four areas with depths exceeding 50 feet : (1) a small area near the 
east end, based on a sounding of 52 feet; (2) the main 50-feet area, 
which encloses the deepest part of the loch, over a mile in length, and 



FIG. 43. LOCH EILT, LOOKING EAST. 

(Photograph by Mr. David Brigham.) 



with a rocky islet rising to the surface near its western margin ; 
(3) a small area between the large island (Eilean Mor) and the northern 
shore, based on a sounding of 55 feet; and (4) a small area near the 
west end, based on two soundings of 55 feet. At the extreme west end 
of the loch, between the two islands, a depth of 40 feet was recorded. 
The 75-feet area is about half a mile, and the 100-feet area about a 
quarter of a mile, in length, occupying the wide central part of the 
western basin, but rather nearer the east than the west end. The 
deepest part of the loch falls below sea-level (the 100-feet contour-line 



THE FRESH-WATER LOCHS OF SCOTLAND. 



251 



corresponding approximately with the level of the sea), and is flat- 
bottomed in character, as shown in cross-section C-D on the map. 

The areas between the consecutive contour-lines drawn in at equal 
intervals, and the percentages to the total area of the loch, are as 
follows : 



to 25 feet 
25,, 50 
50,, 75 
75,, 100 
Over 100 , 



187 acres 

111 

88 

20 

18 

424 



per cent. 



26-0 

20-9 

4-8 

4-2 

100-0 



Temperature Observations. The temperature of the surface water 
in Loch Eilt during the two days spent on it varied from 58 to 60 
Fahr. On July 10, 1902, three series of temperatures were taken 
beneath the surface, one in each of the three basins into which the loch 
is divided, with the following results : 



Depth in feet. 



Loch Eilt (eastern 

basin). 

July 10, 1902, 
2-30 p.m. 



Loch Eilt (central 

basin). 

July 10, 1902, 
3'30 p.m. 



Loch Eilt (western 

basin). 

July 10, 1902, 
5p.m. 



Fahr. 


Fahr. 3 Fahr. 


Surface. 58*0 


58-1 


60-0 


10 


58O 


58-1 


60-0 


20 


58-0 


58-1 


60-0 


27'5 


55-7 


57-7 


60-0 


35 


52-8 


53-6 


59-7 


50 


50-7 


52-8 


54-8 


75 




... 


53-0 


100 


... 


... 


51 -0 



These series show a constant temperature down to 20 feet in each 
case, but the water in the deep western basin was 2 warmer than in 
the other two basins. Beyond the depth of 20 feet, again, the tem- 
perature was about 2 higher in the western basin than in the central 
basin, and 2 higher in the central basin than in the eastern basin, so 
that at a depth of 100 feet in the western basin the temperature was 
rather higher than at a depth of 50 feet in the eastern basin. The 
water in the western basin was warmer at all depths than that in the 
central basin, and in the central basin than in the eastern basin. To 
explain this peculiar distribution of temperature in the waters of Loch 
Eilt on the afternoon of July 10, 1902, the weather conditions during 
the few preceding days must be taken into account. The wind had 
been blowing strong from the north-east from the 3rd till the afternoon 
of the 9th. Rain commenced to fall about 6 a.m. on the 9th, and 
continued till about 8 a.m. on the 10th, so that during the twelve hours 
from 9 p.m. on the 9th to 9 a.m. on the 10th the surface of the loch rose 



252 BATHYMETRICAL SURVEY OF 

9J inches. About 11.30 a.m. on the 10th the wind rose from the west, 
and by 4 p.m. was blowing a gale, so much so that the greatest difficulty 
was experienced in keeping the boat in position for the 5 p.m. series 
of temperatures. It would thus appear that the easterly winds of the 
previous week had blown the warm surface water into the western 
portion of the loch, and the west wind of the 10th had not yet had 
time to reverse this effect; the fact that the area draining into the 
western basin is nearly double that draining into the other two basins 
would doubtless accentuate this result, since more water would enter 
the western basin than the other basins, and this inflowing water at 
this season of the year would be warmer than the water of the loch. 
The range of temperature from surface to bottom in the eastern basin 
was 7-3 Fahr., the greatest fall being 5-2 between 20 and 35 feet; 
in the central basin the range was 5'3, the greatest fall being 4-5, 
also between 20 and 35 feet; in the western or main basin the range 
was 9 (representing the extreme range observed throughout the entire 
loch), and the greatest fall was 4-9 between 35 and 50 feet. 



THE FRESH- WATER LOCHS OF SCOTLAND. 253 



LOCHS OF THE NAN UAMH BASIN. 

THE lochs to be dealt with here are Loch Dubh, between the head of 
Loch Ailort and the head of Loch nan Uamh, and Lochs Mama and 
na Creige Duibhe lying to the north-east. Loch Doir' a' Gherrain in 
Ardnish could not be sounded, because there was no boat on it at the 
time of the visit of the Lake Survey. 

Loch Dubh (see Plate LVL). Loch Dubh is a small loch situated 
at the head of the peninsula of Ardnish, which separates Loch Ailort 
from Loch nan Uamh, the two branches of the sound of Arisaig. The 
Mallaig extension of the West Highland railway runs along its southern 
shore, and the outfall flows through the old bed of the little Lochan 
Deabhta, which has been completely drained by the railway, leaving 
only a channel through it for the escape of the waters from Loch Dubh. 
After leaving Lochan Deabhta the outfall joins the Schoolhouse burn, 
which has been deflected, thence into the Arnabol burn, falling into 
the head of Loch Beag, an inlet of Loch nan Uamh. It is surrounded, 
except on the western side, by low though steep hills, which impart 
a dark and sullen appearance to the loch, hence its name the Black 
loch. Considering its superficial area, it is the deepest loch visited by 
the Lake Survey.* Its great depth, and the remarkable temperature 
conditions discovered in it, well repaid the trouble pf carting a boat 
from Loch nan Uamh and carrying it down to the loch. Its catchment 
area is very small, and it would seem that the unpleasant taste of its 
water, resembling that of a stagnant pool, is due to the small amount 
of fresh water entering it. This unpleasantness is probably something 
more than mere taste, for attempts to stock the loch with trout have 
been unsuccessful, the fish rapidly dying ; eels, however, abound in it. 

Loch Dubh trends in a north-west and south-east direction, the 
broadest part being rather nearer the south-east end. Its length is 



* The deepest lake in East Prussia is, according to Halbfass (Globus, Bd. 86, p. 187, 
September 15, 1904), the Wuchsnigsee, which is about 1J miles in length, and has a 
maximum depth of about 210 feet. Loch Dubh is less than half a mile in length, and its 
maximum depth is 153 feet. 



254 BATHYMETRICAL SURVEY OF 

under half a mile, its maximum breadth one-sixth of a mile, and its 
mean breadth one-tenth of a mile. Its waters cover an area of about 32 
acres, and it drains an area eight times greater, or about 262 acres. 
Sixty-five soundings were taken, and the maximum depth observed was 
153 feet, which bears the ratio to the length of the loch of 1 to 15. 
This low ratio is only equalled by the little loch on Eilean Subhainn 
in Loch Maree, and the loch which most nearly approaches it is Loch 
Fender in the Tay basin, in which the ratio is as 1 to 22, followed by 
Loch Dhugaill, near Kishorn, in which the ratio is as 1 to 27. Among 
the larger Scottish lochs, the nearest approach is found in Loch Treig, 
with a ratio of depth to length of 1 to 62. The volume of water 
contained in the loch is estimated at 86,956,000 cubic feet, and the mean 
depth at nearly 63 feet, or 41 per cent, of the maximum depth. The 
loch was surveyed on July 12, 1902; the elevation of the lake-surface 
above the sea was found, by levelling from bench-marks, to be 103-0 
feet ; when visited by the Ordnance Survey officers on August 6, 1869, 
the elevation was 103*3 feet above sea-level. No drift-marks were seen, 
but the keeper stated that the annual range in level was about 9 inches. 
Loch Dubh is very simple in conformation, the contour-lines follow- 
ing approximately the shore-line. Near the north-west end there is a 
slight rise of the bottom, as shown in section A-B on the map, but 
otherwise the lake-floor slopes down regularly to the deepest part, 
which lies towards the north-eastern shore. The maximum depth of 
153 feet was observed at a distance of about 120 feet from this shore, 
giving a slope of 59 ; the height of the hill immediately adjoining is 
240 feet, and the slope 35, hence the slope from the top of the hill to 
the bottom of the loch is one of 45. The areas between the consecutive 
contour-lines drawn in at equal intervals, and the percentages to the 
total area of the loch, are as follows : 

Oto 50 feet 14 '8 acres 407 per cent. 

50,, 100 ,, 8-9 30-9 

100,, 150 ,, 7-6 26-5 

Over 150 , 0'5 . 1-9 



31-8 . 100-0 



Temperature Observations. A most interesting series of temperatures 
was taken in Loch Dubh at the time of the survey, as given in the first 
column of the following table. The loch was revisited in March, 1903, 
when the water was found to be uniform in temperature from surface 
to bottom, as given in the second column of the table 



THE FRESH-WATER LOCHS OF SCOTLAND. 



255 









Depth in feet. 


Loch Dubh. 
July 12, 1902, 
3 p.m. 


Loch Dubh. 
March 28, 1903. 




Fahr. 


Fahr. 





59-0 


41-0 


10 


59-0 




16 


58-9 


tt 


20 


56-0 


.. 


25 


53-7 




35 


51-5 




50 


47-1 


41-0 


75 


44-1 


41-0 


100 


43-6 


40-9 


150 


43-5 


40'9 






The series taken in March calls for no discussion, but the series 
taken in July is remarkable for the low temperature of the deep water 
at this season of the year, and for the great range of temperature from 
surface to bottom. Compared with the temperatures recorded in Loch 
Shiel a week earlier in the same month, we find the temperature in 
Loch Dubh l-7 lower at the bottom in 150 feet than in Loch Shiel in 
420 feet, and in Loch Morar (the deepest of all Scottish lochs), ten days 
earlier in the same month, a temperature equal to that at the bottom 
of Loch Dubh was recorded only after descending to a depth of 250 
feet. The extreme range of temperature shown by the series in Loch 
Dubh amounts to 15*5, while the series taken in Loch Shiel shows a 
range of only 12, and the series in Loch Morar shows a range of only 
13, from surface to bottom. The extraordinary temperature conditions 
observed in Loch Dubh may probably be accounted for (1) by the great 
depth of the loch compared with other lochs of similar area ; (2) by the 
small extent of its drainage area, so that very little rain-water enters 
the loch ; and (3) by the small area of the loch and the steepness of the 
surrounding hills reducing the mixing effect of the wind to a minimum. 

Lochs Mama and na Creige Duibhe doubtless formed at no distant 
date one sheet of water, which was gradually separated into two portions 
by the deposition of material brought down by the Allt Dearg. This 
is evidenced by the fact that locally the name Mama is applied to 
both divisions, but in this place that name is restricted to the western 
basin, the name na Creige Duibhe being applied to the larger and 
deeper eastern basin. The connecting stream is about 60 yards in 
length, with a depth of 7 to 8 feet, the fall from Loch na Creige Duibhe 
to Loch Mama being less than a foot. The tract of alluvium separating 
the two lochs was about 2^ feet above the water of Loch Mama, and 
the keeper stated that he had often seen it flooded when the lochs were 
high. The hills along the northern and southern shores of the lochs 
rise steeply up to heights exceeding 1000 feet, approaching 2000 feet 
along the northern shores, down the sides of which a few torrents rush 



256 BATHYMETRICAL SURVEY OF 

after heavy rains. The two lochs trend east and west, and the outflow 
from Loch na Creige Duibhe passes into Loch Mama, and thence by 
the Gleann Mama into Loch nan Uamh. 

Loch Mama (see Plate LVL). Loch Mama is over one-third of a 
mile in length, one-eighth of a mile in maximum breadth, and one- 
twelfth of a mile in mean breadth. Its waters cover an area of about 
17 acres, and it drains directly an area of two-thirds of a square mile, 
but since it receives the outflow from Loch na Creige Duibhe its total 
drainage area is over 2 square miles, an area seventy times greater than 
that of the loch. Nearly 40 soundings were taken, the maximum depth 
observed being 44 feet. The volume of water contained in the loch is 
estimated at 11 million cubic feet, and the mean depth at 14 J feet. The 
loch was surveyed on July 11, 1902, and the elevation of the lake- 
surface above the sea was determined from spot-levels as being 359 
feet. It forms a simple basin, the deepest part being found towards 
the east end. The areas between the contour-lines, and the percentages 
to the total area, are as follows : 

bo 10 feet 8'0 acres 46 '9 per cent. 

10,, 25 6-4 ,, 37-5 

Over 25 , 2'6 , 15 "6 



170 , 100-0 



Loch na Creige Duibhe (see Plate LVL). Loch na Creige Duibhe is 
four-fifths of a mile in length, one-eighth of a mile in maximum breadth, 
and one-fourteenth of a mile in mean breadth. Its waters cover an 
area of about 36| acres, and it drains an area twenty-four times greater, 
or about 1 \ square miles. Over 70 soundings were taken, the maximum 
depth recorded being 93 feet. The volume of water is estimated at 
52 million cubic feet, and the mean depth at 32 \ feet. The loch 
was surveyed on the same day as Loch Mama (July 11, 1902); the 
elevation of the lake-surface above the sea, from spot-level and by 
comparison with Loch Mama, was found to be 359*7 feet. An inspection 
of the map shows Loch na Creige Duibhe to be (like Loch Mama) a long 
narrow basin of very simple conformation. It is much deeper than Loch 
Mama, and the deeper water approaches nearer to the west than to the 
east end, that is to say, nearer to the alluvial cone separating the two 
lochs. A similar state of matters has been noted in the case of Lochs 
Voil and Doine in the Forth basin, formerly a continuous loch, now 
divided into two portions by the deposition of material brought down 
by the river, where deep water approaches close to the dividing 
promontory of land on both sides. * 

The areas between the consecutive contour-lines drawn in at equal 

* See p. 9. 



THE FRESH- WATER LOCHS OF SCOTLAND. 257 

intervals, and the percentages to the total area of the loch, are as 

follows : 

to 25 feet 21 '2 acres 58 '1 per cent. 

25 50 ,, 6-9 19-0 

50,, 75 5-1 14-1 

Over 75 , 3-2 , 8 '8 



36-4 , 100-0 



Temperature Observations. The surface temperature observed in 
Loch na Creige Duibhe on the date of the survey was 57'4, in the 
stream between the two lochs 57'l, and in Loch Mama 56'5. The 
following serial temperatures were taken in the deepest part of Loch 
na Creige Duibhe at 4.45 p.m. on July 11, 1902 : 

Surface 57'4 Fahr. 

10 feet 57'4 

20 ,, 57'4 

30 ,, 53-0 

50 ,, 50'8 ,, 

75 49-2 

90 ., - 48'S 

This series shows a constant temperature down to 20 feet, then a 
fall of 4-4 between 20 and 30 feet, and a further fall of 2-2 between 
30 and 50 feet, the extreme range of temperature from surface to bottom 
being 8-6. 

The details regarding the lochs in the Shiel, Ailort, and nan Uamh 
basins are collected together in the table on p. 258 for convenience of 
reference and comparison. From this table it will be seen that in the 
six lochs under consideration nearly 1200 soundings were taken, and 
that the aggregate area of the water-surface is over 8J square miles, so 
that the average number of soundings per square mile of surface is 139. 
The aggregate volume of water contained in the lochs is estimated at 
about 29,000 millions of cubic feet. The area drained by these lochs 
is nearly 100 square miles, or 11 J times the area of the lochs. 

Geology of the Loch Shiel Catchment Basin. Though the basin of 
Loch Shiel has not been surveyed by the Geological Survey, we under- 
stand that certain members of the staff have examined the rock cuttings 
on the line of railway between Loch Eil and Kinlochailort. The rocks 
exposed in these cuttings consist of muscovite-biotite gneiss and flaggy 
mica-schists, which are included in the Moine series of crystalline 
schists by the Geological Survey. The general strike of these strata 
is north-east and south-west, so that in all likelihood they are continued 
to the south-west along both sides of Loch Shiel. This conclusion is 
supported by the fact that on the lofty watershed between Loch Shiel 



258 



BATHYMETRICAL SURVEY OF 



a 

R 

e 

I 

B ^ 

^ * 



55 .5 






s> 


Ratio to 
area of 
loch. 


O CO CC O CO CO ^ 

co o5 c^i "^ co co co 

f^H 00 00 00 <* O5 < i 
p-H 1C r-t <N CO 1 


1 


ill 


* 

C^ r i IO i I CO O5 !> 
* 00 O "* * O O5 

g 2 2 ^ ^ i 


c 
1 


11 


S ^ cp 8 8 p S 

t^ O O O O O 00 


Volume 


in minion 
cubic feet. 


QC ^ 00 CC ^O >-^ CO 
Oi> ^ -1 * CO Oi> 


h 


1 


g ^ 01 CO 1^ 


g 

p 

03 


X 


O^ t^* Ot) *O ^7 ^ 

s co 2 - ^ 




s l"s 


CO t> O5 P O5 ip 

^H (70 ^H ^H 4t< 6) 

CO rfH CO -* CO CO 


I 


ll 


CO (M CO CO OO I 




II 


| S S g 3 


Mean 
breadth 


1^1 


C^ O 1 ^O CC 00 ^~* 
S! - SI 5 


d 


1 


CO O O O !> 00 

T< ~- 1 (55 r-H p P 

O O O O O O 


I a 




oo t^ ^H t^ co co 

00 CO ^H F-H r-H 




1 


O O O O O O 


! 


1 


1^- ^H CO O O O 


1^ 

3 


It 


O C * O ^ 00 i 

^ 2 




r 


1 1 

1 


TH P ^ p 1- P 




i 


.1 

" "S J " o S 
1 S 3 & S x 



THE FRESH- WATER LOCHS OF SCOTLAND. 259 

and Loch Linnhe these muscovite-biotite gneisses have been mapped by 
the Geological Survey. These schists and gneisses, which are supposed 
to represent altered sediments, are traversed by numerous veins of 
pegmatite and dykes of diorite, dolerite, and basalt. 

On the watershed between Glen Hurich and Glen Scaddle, on the 
crest of Sgor Dhomhail (2915 feet), there is a mass of foliated granite, 
and, further to the south-west, the later igneous intrusions of the 
Strontian district may enter the Loch Shiel catchment basin. 



NOTES ON THE BIOLOGY OF THE LOCHS IN THE SHIEL DISTRICT. 
By JAMES MURRAY. 

Of the six lochs surveyed, tow-nettings were taken in four, and a 
shore-netting in a fifth. The biology presented little of special interest. 
Diaptomus laciniatus was found in two of the lochs (Shiel and Eilt) ; 
these are the most southerly lochs in which this northern species was 
observed by the Lake Survey, though it has been recorded by Dr. Scott 
from one loch (Loch Doon) much farther south. 

Loch Shiel. Owing to the great abundance of Holopedium, which 
choked up the nets, it was difficult to collect other animals in any 
numbers. The most plentiful animals were : Diaptomus gracilis, 
Diaptomus laciniatus, Cyclops strenuus , Bosmina obtusirostris, Bytho- 
trephes, Polyphemus, six species of pelagic Rotifers (including Flos- 
cularia pelagica), and Dinobryoii. The plants noted were : Xanthidium 
antilopeum, Staurastrum gracile, and Staurastrum braziliense. Lobelia 
and LittnreUa were in flower at the upper end of the loch. 

Loch Dilate. As compared with Loch Shiel, the most notable 
features of this loch were : the greater abundance of life, the absence of 
Holopedium and Diaptomtw Jaciniatus, and the presence of Diaphajio- 
soma brachyurum in considerable numbers. Among the organisms 
observed were: Diaptomus gracilis, Cyclops strenuus, Synchceta 
pectinate, Plcesoma truncata, Dinobryon, Peridiniu?n, two species of 
Ceratium (C . hirundinella and C . cornutum), Anabce.ua flos aqua with 
its adherent Vorticellce. 

Loch Eilt. Life was abundant, the characteristic animals being 
Holopedium, Diaptomus laciniatus, Cyclops strenuus, Anurcea cochlearis, 
Notholca longispina, and Polyarthra. Leptodora and Bythotrephes were 
scarce. Bosmina obtusirostris and a variety approaching B. longispina 
were seen. The brilliant red and blue Rotifer, Notops pygmceus, was 
plentiful. Some immature specimens of Diaptomus probably belonged 
to D. gracilis. On the mud in the deepest part of the loch were numbers 
of a pretty little green larva of an insect, enclosed in transparent flask- 
shaped cases. 



260 BATHYMETRICAL SURVEY OF 

Loch Dubh. This little loch, remarkable for its great relative depth 
and temperature conditions, resembling those in a great lake, was 
examined on two occasions. On the first visit in July, 1902, the surface 
temperature was 59 Fahr., while on the second visit in March, 1903, 
the temperature throughout was about 41 Fahr. Notwithstanding 
this difference in temperature there was little difference in the animals 
observed on the two occasions. Those found in July were : Diaptomus 
gracilis (blue and red, grey, red, blue), Cyclops strenuus, Bosmina 
obtusirostris (small, purple), Daphnia lacustris (all pale red), Eurycercus, 
Polyphemus, Triarthra, Polyarthra, Anurcea cochlearis, Conochilus, 
Ceratium hirundinella, Dinobryon. In March all. the same animals 
were found, except Polyphemus, and there were in addition a few larvae 
of Corethra (phantom larvae), Notholca foliacea, a second species of 
Ceratium (C . cornutum less common in lakes), Mallomonas. A very 
small form of Asterionella occurred. Near the shore large spheres of 
Ophridium were found on the weeds. In the mud from the bottom were 
many Rhizopods of the species Cyphoderia ampulla, Difflugia pyri- 
formis, D. globulosa, and D. arcula. Lobelia and Myriophyllum were 
growing along the shores. 

Loch na Creige Duibhe. As this loch was only examined by means of 
a net thrown out from the shore, it is probable that some of the pelagic 
animals may have been missed. The animals seen were : Diaptomus 
gracilis (reddish), Cyclops strenuus (yellow), Alonopsis elongata, 
Chydorus sphcericus, Anurcea cochlearis, Bosmina obtusirostris, Arcella 
vulgar is. A few of the commonest filamentous Algae and Desmids were 
seen. Asterionella was scarce. 






THE FRESH- WATER LOCHS OF SCOTLAND. 261 



LOCHS OF THE CONON BASIN. 

FOURTEEN lochs draining into the Cromarty firth were surveyed by the 
staff of the Lake Survey, viz., Lochs Crann, a'Chroisg, Gown, Achanalt, 
a* Chuilinn, Fannich, Luichart, Beannachan, Achilty, Garve, Kinellan, 
Ussie, Glass, and Morie. The majority of these lochs drain by the river 
Conon into the head of the Cromarty firth, while Lochs Glass and Morie 
drain by independent streams, which fall into the Cromarty firth on 
its north-western shore. It has been found convenient, also, to include 
in this place a description of Loch Eye, situated between Cromarty 
firth and Dornoch firth. The drainage area under consideration is 
indicated in the index map of the district (Fig. 44), by reference to 
which the relations between the various lochs will be readily understood, 
and extends from the mouth of the Cromarty firth on the east to the 
heights of Carn Breac and An Groban on the west, Carn Chuinneag 
on the north, and Sgorr a' Choir-Ghlais on the south. The total area, 
as measured by the planimeter on the 1-inch Ordnance Survey maps, is 
over 770 square miles, and of this total 336 square miles (or one-half) 
drain into the lochs now to be dealt with, as will be seen from the 
summary table. 

The headwaters of the basin take their rise on the flanks of Carn 
Breac, flowing by various streams into Loch na Moine Moire and Loch 
an t-Sior (which were not sounded), thence into Loch Crann and Loch 
a' Chroisg, the outflow from which is carried by the river Bran into 
Loch Achaualt and Loch a' Chuilinn, and thence into Loch Luichart. 
Shortly after leaving Loch a' Chroisg the river Bran receives the outflow 
from Loch Gown, which is fed by the Allt Gharagain, taking its rise 
on the flanks of Moruisg (3026 feet), and shortly before entering Loch 
Luichart the river Bran is joined by the river Fannich bearing the 
outflow from Loch Fannich, which is fed by various streams draining 
the flanks of a grand series of mountains exceeding 3000 feet in height. 
After the junction of the Bran and the Fannich the river receives the 
name of Conon, and shortly after leaving Loch Luichart it is joined by 
the river Meig, bearing the outflow from Loch Beannachan, taking its 
rise among lofty mountains culminating in Sgurr a' Chaoruinn (3452 
feet). Still further on the river Conon is joined by the Black Water, 
bearing the outflow from Lochs Garve and Achilty, and taking its rise 



262 



BATHYMETRICAL SURVF.Y OF 



far to the north on the flanks of Beinn Dearg (3547 feet). Still further 
on the river Conon is joined by the river Orrin, and finally falls into 
the head of the Cromarty firth at Dingwall. The river Glass, which 
in its course flows through Loch Glass, rises on the flanks of Beinn nan 
Eun, and empties itself in the Cromarty firth at Balconie Point. The 
river Alness, which flows through Loch Morie, rises on the flanks of 
Beinn a' Chaisteil, and falls into the Cromarty firth at Alness Point. 
The geology of the district is dealt with by Drs. Peach and Home, 
whose notes are appended, as well as a few biological notes by Mr. James 




O I 2 3 4 5 



' English Miles 



FIG. 44. INDEX MAP OF THE CONON BASIN. 

Murray. Mr. R. M. Clark, B.SC., who took part in the survey of the 
lochs in the Conon basin in 1902, has supplied us with several series 
of temperatures taken by him the previous summer (1901) in Lochs 
Achilty, Garve, Achanalt, a' Chuilinn, and a' Chroisg, which are here 
incorporated.* 



* These temperature observations, taken by Mr. Clark in the summer of 1901, are 
interesting, as compared with the observations taken in the same lochs in the summer 
of 1902, when viewed in connection with the atmospheric conditions in the two seasons. 
It will be observed that all the readings taken in the superficial waters of these lochs 
in 1901 are higher than those taken in 1902, and this is evidently related to the warmer 
season in the first-named year. Thus the mean temperature over Scotland for July, 

1901, was 61-8 Fahr., or 3 above the long-period average for that month, while for July, 

1902, it was 54-4, or 4 below the average ; for August, 1901, tie mean was 57 0< 5, or 
1 above the average, while for August, 1902, the mean was 53 '9, or 2^ below the average. 
The nearest station to the Couon basin lochs from which observations are available is 
Inverness, and the mean temperature there for July, 1901, was 61-0, or 4 above the long- 
period average, while for July, 1902, the mean temperature was 45-4, or 3 below the 



THE FRESH-WATER LOCHS OF SCOTLAND. 263 

Loch Crann (see Plate LVIL). Loch Crann is a small shallow loch 
situated a short distance to the west of Loch a* Chroisg, and lying at a 
slightly higher level. Its striking characteristic is the large area of 
hilly country draining into it an area nearly 600 times greater 
than that of the loch. It is roughly quadrangular in outline, with a 
maximum diameter of less than a quarter of a mile, and it covers an 
area of about 13J acres, 80 per cent, of which is under less than 10 feet 
of water. The deeper soundings were taken in the southern half of the 
loch, the maximum depth observed being 17 feet. The volume of water 
is estimated at 4 million cubic feet, and the mean depth at nearly 
7 feet. Loch Crann was surveyed on August 19, 1902, when the level 
was determined as being 513'7 feet above the sea. The temperature of 
the surface water at 5 p.m. on that date was 59*6 Fahr., and at a 
depth of 14 feet 56-2. 

Loch a' Chroisg (see Plate LVIL). Loch a' Chroisg (or Loch 
Rosque) is^ne of the larger and more important lochs within the basin, 
lying amid beautiful scenery, the hills on both sides rising to heights 
exceeding 1500 feet, and culminating in Meall a' Chaoruinn (2313 feet) 
on the northern shore (see Fig. 45). It is a good trout loch, and char 
also occur, but the fishing is strictly preserved. The loch trends almost 
due east and west, though very slightly sinuous in outline ; the shore-line 
is on the whole very regular, except that two conspicuous alluvial cones 
have been laid down on the northern shore at the mouths of the Allt 
Duchairidh and neighbouring stream. The loch is 3J miles in length, 
with a maximum breadth of nearly half a mile, the mean breadth being 
over a quarter of a mile. Its waters cover an area of about 640 acres 
(1 square mile), and it drains directly an area of over 1\ square miles, 
but, as it receives the outflow from Loch Crann, its total drainage area 
is over 19 square miles. The maximum depth of 168 feet was observed 
approximately near the centre of the loch, opposite the mouth of the 
Allt Duchairidh entering the loch on its northern shore, and about 2 
miles from the east end. The volume of water contained in the loch is 
estimated at 2057 million cubic feet, and the mean depth at nearly 74 



average ; for August, 1901, the mean was 58-7, or 2 above the average, while for August, 
1902, the mean was 54-2, or 2 below the average. Sunshine records are available for 
Strathpeffer within the Conon basin during 1 these seasons, and they bear the same relations: 
thus during July, 1901, 162-1 hours of sunshine were recorded at Strathpeffer (or 34-5 above 
the normal for that month, and 30 per cent, of the possible amount), while during July, 
1902, the duration of sunshine was 95-6 hours (or 32-0 below the normal, and 18 per cent, of 
the possible amount) ; during August the difference was not so marked in the two years, 
the duration in August, 1901, being 140-0 hours (or 18-5 above the normal, and 30 per cent, 
of the possible amount), while in August, 1902, the duration was 131-8 hours (or 10-3 above 
the normal, and 28 per cent, of the possible amount). The sunshine records for Inver- 
ness agree closely with those given above for Strathpeffer for the two seasons under 
consideration. 



264 



BATHYMETRICAL SURVEY OF 



feet. The loch was surveyed on July 30 to August 1, 1902, and the 
elevation of the lake-surface, on commencing the survey, was found, by 
levelling from bench-mark, to be 508*4 feet above the level of the sea ; 
when levelled by the Ordnance Survey officers on July 3, 1868, the 
elevation was 507'9 feet above sea-level. 

Loch a' Chroisg forms a simple basin with no pronounced irregu- 
larities of the lake-floor, as is well shown by the longitudinal and 
cross sections on the map; the contour-lines enclose continuous areas 
following approximately the outline of the loch. The 100-feet basin 




FIG. 45. LOCH A' CHROISG, LOOKING WEST. 

(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.X.K.) 



exceeds 2 miles, and the 50-feet basin is nearly 2| miles, in length, 
approaching in each case rather nearer to the east than to the west end 
of the loch, while the small 1 50-feet basin lies nearer to the west than 
to the east end. The approximate areas between the consecutive 
contour-lines drawn in at equal intervals, and the percentages to the 
total area of the loch, are as follows : 



Oto 50 feet 
50,, 100 
100,, 150 
Over 150 , 



241 acres 
186 
195 



640 , 



37 '7 per cent. 
29-0 
30-5 
2-8 



100-0 



The slightly larger area between 100 and 150 feet than between 50 
and 100 feet indicates the flat-bottomed character of the deeper part 



THE FRESH- WATER LOCHS OF SCOTLAND. 



265 



of the loch, and the soundings show in certain places rather steep slopes 
both off the northern and southern shores. 

Temperature Observations. In the following table are given the 
results of a series of temperatures taken in Loch a' Chroisg on August 
22, 1901, by Mr. Clark, and of two series taken by the Lake Survey 
staff on August 1, 1902: 



Depth in feet. 


August 22, 1901 
(R. M. Clark). 


August 1, 1902. 
i mile from E. end 
of loch in 106 feet. 


August 1, 1902. 
Deepest part of loch 
in 156 feet. 




= Fahr. 


Fahr. 


a Fahr. 





58-2 


55-0 


54O 


20 


58-2 


tm 


... 


25 




53-7 


53-9 


40 


58-0 


... 




50 




53-1 


53-2 


60 


57'6 


... 




:-. 




f>3 : 3 


51-0 


80 


51-9 


53-2 




90 




50-5 




100 


48-5 


49-9 


49-1 


120 


47-5 


... 




150 






48-9 



The series taken in 1901 shows a range from surface to bottom 
amounting to 10*7, whereas the two series taken in 1902 show a range 
of only 5 in each case, and an extreme range of 6. The upper layers 
of water down to a depth of 60 feet were much warmer in 1901 than in 
1902, but between 60 and 100 feet the 1901 observations indicated a 
fall of 9 (viz., a fall of 5-7 between 60 and 80 feet, and a fall of 3-4 
between 80 and 100 feet), so that the temperature of the bottom layers 
of water beyond 100 feet was lower in 1901 than was observed at these 
depths in 1902. 

Seiche. On August 19, 1902, between 4.30 and 5.30 p.m., a seiche 
was observed by Mr. James Murray within the shelter of the pier at the 
east end of Loch a' Chroisg, a light west breeze blowing at the time. The 
amplitude was a quarter of an inch, and the period about 11 \ minutes. 

Loch Gown (see Plate LVII.). Loch Gown (or Ledgowan) lies about 
a mile to the south-east of Loch a' Chroisg, and is also a good trout loch, 
but the fishing is preserved. It trends in a north-east and south-west 
direction, is very irregular in outline, and about 1J miles in length. 
Though it may at one time have formed a single lake, it is now divided 
into two distinct lakes having, at the time of the survey, a difference 
in level exceeding 2 feet. This separation has probably been brought 
about mainly by the deposition of material laid down by the Allt 
Mhartuin, and the passage between them is obstructed by weeds, 
so that it is impossible to row a boat from one loch to the other, except 
after heavy floods. The two lochs are nearly equal in superficial area, 
but the southern basin is much deeper than the northern one. 



266 



BATHYMETRICAL SURVEY OP 



South Loch Gown. The southern loch is roughly quadrangular in 
outline, over half a mile in length, and nearly a third of a mile in 
maximum width, covering an area of about 55 acres, while it drains 
an area exceeding 13 square miles. The maximum depth of 52 feet 
was observed relatively close to the north-eastern shore. The volume 
of water is estimated at 38 million cubic feet, and the mean depth at 
nearly 16 feet. The loch forms a simple basin, the 10-feet contour 
following approximately the outline of the loch and extending a short 
distance into the passage leading to the northern loch, and the 25-feet 
basin is centrally placed. Of the entire lake-floor, only 13 per cent, is 
covered by more than 25 feet of water. It was surveyed on August 2, 
1902, when the elevation was determined as being 524-4 feet above the 
level of the sea. 

North Loch Gown. The northern loch is more oblong in outline 
than the southern loch, so that while nearly equal in length its 
maximum width is less, viz., about a fifth of a mile. Its waters cover 
an area of about 48 acres, and it drains directly an area of about 
1 square mile ; but, since it receives the outflow from the southern loch, 
its total drainage area is over 14 square miles nearly 200 times 
greater than the area of the loch. The greatest depth observed was 
17 feet, approximately near the centre of the loch. The volume of 
water is estimated at 14 million cubic feet, and the mean depth at 
nearly 7 feet. A constriction in the outline towards the southern end 
of the loch is accompanied by a slight shoaling of the bottom, the 
result being that a small 10-feet basin near the southern end, with 
a maximum depth of 13 feet, is separated from the large main basin. 
Of the entire lake-floor 22 per cent, is covered by more than 10 feet 
of water. It was surveyed on the same day as the southern loch 
(August 2, 1902), and the elevation was determined as being 522' 1 
feet above sea-level. 

Temperature Observations. Serial temperatures were taken in the 
deepest part of each loch, with the following results : 





North Loch Gown, 


South Loch Gown, 


Depth in feet. 


August 2, 1902, 


August 2, 1902, 




1 p.m. 


4 p.m. 




Fahr. 


Fahr. 


Surface 


557 


55-0 


10 


557 


55-0 


15 


55-7 




20 




55-0 


30 




53-8 


40 


... 


52-1 



In the shallow north loch the temperature was found to be constant 
from surface to bottom, and in the south loch the temperature was 
constant from the surface down to a depth of 20 feet (though more 






THE FRKSH- WATER LOCHS OF SCOTLAND. 267 

than half a degree lower than in the north loch); between 20 and 
30 feet the fall was l-2, and between 30 and 40 feet l-7 a fall of 
nearly 3 in the 20 feet of depth. 

Loch Achanalt (see Plate LVIII.). Loch Achanalt is an irregular 
shallow loch apparently in process of being silted up, the material 
brought down by the river Bran forming two long spits extending out 
towards the centre of the loch. The northern spit extends nearly across 
the loch, joining the islands, and leaving only a narrow passage close to 
the eastern shore, through which there was a strong current, and thus 
practically cutting the loch into two portions. The western shores 
are bordered by weeds. It flows into Loch a' Chuiliiin by a short and 
rapid stream, the difference in level exceeding 4 feet; the Highland 
railway is carried over the passage between the two lochs. Loch 
Achanalt is approximately quadrangular in outline, its maximum 
diameter exceeding three-quarters of a mile, and it covers an area 
of about 160 acres, or one-quarter of a square mile. The deepest water 
was found comparatively close to the western shore, south of the 
entrance of the river Bran, where two soundings of 9 feet and two 
soundings of 8 feet were recorded. The volume of water is estimated 
at 31 million cubic feet, and the mean depth at 4J feet half the 
maximum depth. The area draining directly into Loch Achanalt is 
very large, exceeding 39 square miles ; but, since it receives the outflow 
from Lochs a' Chroisg and Gown, its total drainage area exceeds 
72J square miles, or 290 times the area of the loch. Loch Achanalt 
was surveyed on August 9, 1902, when the elevation of the lake- 
surface was found to be 365*1 feet above the sea; when levelled by 
the Ordnance Survey officers on May 9, 1870, the elevation was 364-7 
feet above sea-level. The temperature of the surface water on the date 
of the survey was 57'l Fahr. ; the temperature of the river Bran being 
55-2. On August 19, 1901, Mr. Clark observed a temperature of 60'l 
at the surface, and a temperature of 60-4 at a depth of 5 feet. 

Loch a' Chuilinn (see Plate LVIII.). Loch a' Chuilinn (or Culen) 
trends east and west, is irregular in outline, of varying width, and with 
an undulating floor. It is 1 J miles in length, with a maximum breadth 
of one -third of a mile. Its waters cover an area of about 113 acres, and 
it drains directly an area of nearly 1J square miles; but as it receives 
the outflow from Loch Achanalt, its total drainage area is over 74 
square miles over 400 times the area of the loch. The maximum 
depth of 43 feet was observed approximately near the middle of the 
loch. The volume of water is estimated at 50 million cubic feet and 
the mean depth at 10J feet. The bottom of Loch a' Chuilinn is most 
irregular; close to the west end is a 10-feet basin, with a maximum 
depth of 29 feet, the slopes of which are in places steep, depths of 20 



268 



BATHYMETRICAL SURVEY OF 



and 21 feet having been found close inshore. Separated from this 
western basin by an interval of about 600 yards, in which the depth 
does not exceed 8 feet, lies the central 10 -feet basin, enclosing the 
maximum depth of the loch (43 feet), and here again the slope is steep, 
one sounding of 29 feet being recorded close to the southern shore. 
Separated from this central basin by a short interval, 7 feet in depth, 
is a small eastern basin, with a maximum depth of 29 feet, and after 
another shallow interval the water deepens at the exit of the outflowing 
river, where soundings of 13 feet were taken. Of the entire lake- 
floor, 75 acres (or 67 per cent.) are covered by less than 10 feet of 
water, and 7 acres (or 6 per cent.) by more than 25 feet of water. 
The loch was surveyed on August 11, 1902, when the elevation of the 
lake-surface was found to be 360'8 feet above the sea. 

Temperature Observations. The following table gives the results of 
observations taken in Loch a' Chuflinn by Mr. Clark on August 19, 
1901, and by the Lake Survey on August 11, 1902: 



Depth in feet. 


Aug\ist 19, 1901 
(R. M. Clark). 


August 11, 1902. 




Fahr. 


Fahr. 





60-3 


557 


5 


60-0 




10 


59-6 




15 




55-4 


20 


59-6 




30 


... 


54 : 7 


40 


58-6 


... 



These observations show that the whole body of water was much 
warmer in 1901 than at the same season in 1902, the difference amount- 
ing on the average to about 4 ; the range of temperature was in each 
case small. 



Loch Fannich (see Plate LIX.). Loch Fannich is the largest within 
the Cromarty firth drainage-basin, and is surpassed in depth only by 
Loch Glass. It is situated in Fannich deer forest amid splendid scenery 
(see Fig. 46), the mountains along the northern shore rising to heights 
exceeding 3000 feet, including An Coileachan (3015 feet), Meallan 
Rairigidh (3109), Sgurr Mor (3637), Sgurr nan Clach Geala (3500), 
Sgurr Breac (3000), and a' Chailleach (3276). The trout fishing is 
good, the fish being of fair size, but the loch is strictly preserved. 
The general trend of the loch is east and west, but the two ends have 
a tendency to bend slightly to the northwards. Loch Fannich is nearly 
7 miles in length, the maximum breadth exceeding three-quarters of a 
mile, and the mean breadth is over half a mile. Its waters cover an area 
of 2300 acres (or over 3J square miles), and it drains an area ten times 



THE FRESH-WATER LOCHS OF SCOTLAND. 269 

greater (over 35 \ square miles). The maximum depth of 282 feet was 
observed about 1J miles from the east end, and about 5J miles from the 
west end. The volume of water is estimated at 10,920 millions of cubic 
feet, and the mean depth at nearly 109 feet. Loch Fannich forms a 
simple basin, all the contour-lines enclosing continuous areas, though 
the deepest part (exceeding 200 feet in depth) lies in the eastern 
half of the loch. The 50-feet area extends from end to end, coinciding 
approximately with the outline of the loch. The 100-feet area 
approaches to within half a mile from both ends, and is nearly 6 miles 
in length ; there is a slight shoaling of the water opposite Rudha Mor 




FIG. 46. LOCH FANNICH, LOOKING EAST. 

(Photoyraph by Mr. T. N. Johnson. M.B., C.M., F.R.S.E.) 



to 103 feet, with deeper water to the east and west. The 1 50-feet area 
is distant over 2J miles from the west end, and is over 3 miles in 
length. The 200-feet area is 2| miles, and the 250-feet area If miles, 
in length, and they approach to within three-quarters of a mile from 
the east end. The slight shoaling opposite Rudha Mor has already been 
referred to, and a similar shoaling is observable within the 200-feet 
contour opposite Fannich Lodge, where the depth decreases from 226 
feet to 212 feet, and increases again on proceeding eastwards into the 
250-feet area ; these two shoalings are indicated in the longitudinal 
section A-B on the map. A sinuosity is also seen in the 200-feet contour 
off the southern shore, opposite Fannich Lodge, due to the shoaling of 
the water from 202 to 191 feet, but on the whole the lake-floor may 
be said to be extremely regular in conformation. The cross section 



270 



BATHYMETRICAL SURVEY OF 



C-D is taken across the loch in the position of the deepest sounding. 
The areas between the consecutive contour-lines drawn in at equal 
intervals, and the percentages to the total area of the loch, are as 
follows : 

to 50 feet 658 acres 28-6 per cent. 



50,, 100 
100 150 
150,, 200 
200,, 250 
Over 250 



582 
418 
272 
220 
155 

2305 



25-2 

18-1 

11-8 

9-6 

6-7 

100-0 



The regularity of the average slope of the bottom is indicated by 
the gradually decreasing areas between the contour-lines, and the 
comparatively large area within the deepest contour indicates the 
flat-bottomed character of the deeper part of the loch. 

Loch Fannich was surveyed on August 13 and 14, 1902, and the 
elevation of the lake-surface was found, on commencing the survey, to 
be 821 '9 feet above sea-level, which is identical with the level observed 
by the Ordnance Survey on May 27, 1870. 

Temperature Observations. The temperature of the surface water 
during the two days spent on the survey varied from 52'7 Fahr. to 
58 00 1. Two serial temperatures were taken on August 14, 1902, with 
the following results : 



Depth in feet. 


August 14, 1902, 
4-1.5 p.m. 
Deepest part of loch. 


August 14, 1902, 
5-30 p.m. 
South-east Of Rudha 
Mor. 




Fahr. 


Fahr. 


Surface 


53-0 


54-0 


5 


52-0 


... 


10 


51-9 




20 


51-6 


53-0 


40 




52-5 


50 


51'0 




70 




50 : 


100 


48 '-6 


467 


130 


... 


457 


150 


45-6 




200 


44-9 


... 


250 


44-5 




281 


44-4 


... 



Each of these series shows a range from surface to bottom of about 
8J. The temperature was higher in the upper 40 feet of water towards 
the west end of the loch than in the deep water towards the east end, 
but at the depth of 100 feet the temperature was 2 lower in the former 
position. Off Rudha Mor there was a fall of 2-5 between 40 and 70 
feet, and a further fall of 33 between 70 and 100 feet (equal to 5'8 in 



. THE FRESH-WATER LOCHS OF SCOTLAND. 271 

the 60 feet of water), while in the deepest part there was a fall of 2-4 
between 50 and 100 feet, and a further fall of 3 between 100 and 150 
feet (equal to 5 -4 in the 100 feet of water). All the observations 
indicate a range of temperature throughout the entire body of water 
amounting to 13*7. 

Loch Luichart (see Plate LX.). Loch Luichart is another large and 
important loch within the Cromarty firth drainage basin, second as 




FIG. 47. LOCH LUICHART, LOOKING ACROSS THE HEAD OF THE LAKE. 

(Photograph by Mr. David Brigham.) 



regards length only to Loch Fannich, though slightly inferior as regards 
superficial area to Loch Glass. It is a good fishing loch situated amid 
grand scenery, where Strath Bran bends to the south-east to join Strath 
Conon (see Fig. 47). Its general trend is north-west and south-east, 
bending round the base of Sgiirr Mairc-suidhe, and it is broadest at the 
north-west end, narrowing towards the south-east. It is 5 miles in 
length, with a maximum breadth of nearly a mile, the mean width being 
one-third of a mile. Its waters cover an area of about 1130 acres, or 
1J square miles, and it drains directly an area of about 39 \ square miles, 



272 BATHYMETRICAL SURVEY OF 

but since it receives the outflow from all the lochs described in the 
preceding pages, its total drainage area is very large about 149J 
square miles, an area 85 times greater than the area of the loch. The 
maximum depth of 164 feet was observed about 1J miles, or about 
one-third of the length of the loch, from the north-west end. The 
volume of water is estimated at 3288 millions of cubic feet, and the 
mean depth at nearly 67 feet. The loch was surveyed on August 16, 
1902, when the elevation of the lake-surface was found to be 249-8 feet 
above the sea. 

The floor of Loch Luichart is irregular, there being three 50-feet 
basins separated by shallower water. The largest and deepest lies in the 
wider north-western half of the loch, and is about 2J miles in length, 
approaching to within less than 200 yards from that end. The central 
50-feet basin is separated from the north-western basin by an interval of 
half a mile, in which lies the single small island in the loch, and where 
the depth in the centre at another place is only 5 feet, and is over 1J 
miles in length. Immediately to the south-east of this central basin 
there is a narrow constriction in the outline of the loch, in which a 
depth of 16 feet was recorded, succeeded by a slight expansion contain- 
ing the third 50-feet basin, with a maximum depth of 55 feet and of 
small extent. The principal 100-feet basin in the north-western part 
of the loch is nearly 2 miles in length, and encloses the deepest part of 
the loch. Two small subsidiary 100-feet basins lie within the central 
50-feet basin : one based upon an isolated sounding of 100 feet, the 
other near the south-eastern end having a maximum depth of 115 feet. 
The 150-feet basin is nearly a mile in length, and is distant three- 
quarters of a mile from the north-west end of the loch ; the maximum 
depth of 164 feet was recorded near the south-eastern end of the basin. 
It is curious to note the difference in the outline of this 150-feet basin 
as compared with the outlines of the 50 and 100-feet basins enclosing 
it, for, while the shallower contours follow approximately the shore- 
line, and therefore enclose areas widest towards the north-west and 
narrowing gradually in the opposite direction, the 150-feet basin is 
widest towards the south-east and narrows gradually to the north-west 
as the outline of the loch widens out. At the same time the deep basin 
approaches nearer to the northern shore at its north-west end, while it 
approaches nearer to the southern shore at the opposite deeper end, so 
that at the position of the deepest sounding the slope off the southern 
shore is much steeper than off the northern shore, as is well brought out 
in the cross-section C-D 011 the map. The longitudinal section A-B 
down the centre of the loch shows the three basins included in the loch, 
each successively deeper on proceeding towards the north-west end. 
The areas between the consecutive contour-lines, and the percentages 
to the total area of the loch, are as follows : 






THE FRESH-WATER LOCHS OF SCOTLAND. 



273 



Oto 50 feet 
50,, 100 
100,, 150 
Over 150 , 



482 acres 
385 
208 
54 

1129 , 



42 '7 per cent. 
34-1 
18-4 
4-8 



100-0 



Temperature Observations. The following table gives the results of 
observations taken in Loch Luichart by Mr. Clark on August 25, 1901, 
and by the Lake Survey on August 16, 1902 : 



Depth in feet, 


August 25. 1901 
(B. M. Clark). 


August 16, 1902, 
5 p.m. 
Deepest part of loch 
in 152 feet. 


August 16, 1902, 
6p.m. 
Near N.W. end in 
93 feet. 




Fahr. 


Fahr. 


Fahr. 





60-6 


55-9 


56-0 


10 


60-0 


... 




20 


59-6 


55 : 8 


... 


40 


59-1 


- 




50 


_ 


54 : 8 


56-0 


60 


57 : 2 




... 


70 







56-0 


75 


... 


5 1-6 


... 


80 


50-9 






90 


... 


... 


48 : 5 


100 


50-5 


48-4 




150 




48-0 





The range of temperature shown by the 1901 observations amounts 
to 10, while that shown by the 1902 observations amounts to 8. The 
temperature of the upper 60 feet of water was higher in 1901 than was 
observed in 1902, as was also the case at a depth of 100 feet, but a 
lower reading was recorded at 80 feet in 1901 than at 70 and 75 feet in 
1902. The two serials taken in 1902 show the effect of the strong wind 
which was blowing up the loch at the time of the survey, the maximum 
temperature observed extending down to a depth of 70 feet near the 
head of the loch, whereas 1J miles further down the loch the temperature 
was always lower, amounting to a difference of l-2 at 50 feet and 4 0< 4 
at 70 feet, beyond which depth a much larger fall of temperature was 
observed towards the head of the loch than was recorded farther down 
(equal to a fall of 7'5 in the interval of 20 feet between 70 and 90 feet 
in the former case, and a fall of 3-2 in the interval of 25 feet between 
75 and 100 feet in the latter case). 



Loch Beannaclian (see Plate LVIIL). Loch Beannachan (or Ben- 
nachran) is situated at the head of Strath Conon, amid wild moorland 
scenery. It trends in a west-north-west and east-south-east direction, 

T 



274 



BATHYMETRICAL SURVEY OF 



narrowing towards the eastern end. It is over If miles in length, with 
a maximum breadth of one-third of a mile, the mean breadth being a 
quarter of a mile. Its waters cover an area of 267 acres, or nearly half 
a square mile, and it drains an area 72 times greater an area exceed- 
ing 30 square miles. The maximum depth of 176 feet was observed 
approximately near the centre of the loch. The volume of water is 
estimated at 819 million cubic feet, and the mean depth at 70 J feet. 
The loch was surveyed on August 22, 1902, when the elevation of the 
lake-surface was found to be 465-6 feet above sea-level; when visited 
by the officers of the Ordnance Survey on June 6, 1870, the elevation 
was 465' 1 feet above the sea. 

Loch Beannachan forms a simple basin, the contour-lines following 
approximately the outline of the loch, but approaching in each case 
nearer to the western than to the eastern end. There is a large wooded 
island at the entrance of the inflowing river at the west end, and a 
small island near the exit of the outflowing river at the opposite end. 
The slope offshore is in some places very steep, especially at certain 
points along the southern shore, and at the position of the deepest 
sounding the slope is steeper off the southern than off the northern 
shore, as is shown in the cross section C-D on the map. The longi- 
tudinal section A-B shows the gradual slope towards the two ends, 
with quite a flat-bottomed character in the deeper water, which is also 
indicated by the larger area between 100 and 150 feet than between 
50 and 100 feet, as given in the following table: 



to 50 feet 
50,, 100 
100 150 
Over 150 , 



113 acres 
67 
72 
15 

267 



42-3 per cent. 
25-0 

27 '2 
5 '5 



100-0 



Temperature Observations. A series of temperatures taken in the 
deepest part of the loch at 4.15 p.m. on August 22, 1902, gave the 
following results : 



Surface 

10 feet 

20 

30 

40 

50 

60 

75 
100 
170 



55'OFahr. 
55 -0 
54 -8 
53 -0 
52 -9 
52 -0 
50 -5 
46 -9 
46 -1 
46 -0 



THE FRESH- WATER LOCHS OF SCOTLAND. 275 

This series shows a range of temperature from surface to bottom 
amounting to 9 Fahr. The upper 20 feet of water was practically of 
uniform temperature, followed by a fall of l-8 between 20 and 30 feet, 
but the greatest fall observed was one of 3 0< 6 between 60 and 75 feet. 

Loch Achilty (see Plate LXL). Loch Achilty is a small but deep 
loch in Torrachilty wood, near Strathpeffer, containing char. In outline 
it is somewhat elliptical, with the long axis trending north-east and 
south-west. It is about 1500 yards in length, by 700 yards in maxi- 
mum breadth, the mean breadth being 450 yards. Its waters cover an 
area of about 147 acres (or nearly a quarter of a square mile), and it 
drains an area exceeding 2 square miles. The maximum depth of 
119 feet was observed about 250 yards from the western shore. The 
volume of water is estimated at 332 million cubic feet, and the mean 
depth at 51 J feet. The floor of Loch Achilty is irregular. The 10-feet 
contour follows approximately the outline of the loch, in many places 
approaching very close to the shore, but the deeper contours are all 
sinuous in character, and there are two small basins exceeding 100 feet 
in depth, the larger and deeper towards the western shore, and the 
smaller, based on a sounding of 112 feet, near the centre of the loch. 
Deep soundings were recorded in some positions near shore, while in 
other positions comparatively shallow soundings were taken some 
distance offshore. A longitudinal section along the axis of maximum 
depth is shown in section C-D on the map. The areas between the 
consecutive contour-lines, and the percentages to the total area of the 
loch, are as follows : 

to 25 feet 41 acres 28-0 per cent. 

25,, 50 28 19-2 

50,, 75 39 26-2 

75,, 100 30 20-2 
Over 100 9 ,, 6*4 ,, 

147 , 100-0 



This table shows a smaller area, and therefore an average steeper 
slope, between 25 and 50 feet, than in the deeper water. The loch was 
surveyed on August 20 and 21, 1902, when the elevation of the lake- 
surface was found to be 98'5 feet above the sea, so that the 100-feet 
contours show approximately the two small portions of the lake-floor 
which lie below the level of the sea. 

Temperature Observations. In the following table are given the 
results of three series of temperatures taken in Loch Achilty by Mr. 
Clark in 1901, along with a series taken in 1902 at the time of the 
survey : 



276 



BATHYMETRICAL SURVEY OF 



Depth in 

feet. 


August 11, 1901 
(B. M. Clark). 


August 23, 1901 
(R. M. Clark). 


September 2, 1901 
(R. M. Clark). 


August 21, 1902 
(Lake Survey). 





Fahr. 

63-5 


Fahr. 
61-9 


Fahr. 


Fahr. 
58-4 


5 


... 


61-9 


t 




10 


62 : 




. 


58 : 1 


20 




61 -5 


. 


57-6 


25 


59 : 4 


57-3 




56-0 


30 




52-0 


t 


54-9 


35 




46-0 




50-9 


40 


460 


44-0 


45 -9 


48-0 


50 




43-2 


43-2 


46-0 


55 




42-8 


42-8 




60 




42-8 


42-8 


... 


70 


42-3 








100 


* . . 


. . . 




44 ! 9 



These serials indicate a most remarkable range of temperature a 
range amounting to 21-2 from the surface to a depth of 70 feet on 
August 11, 1901, and 19 0t l from the surface to a depth of 60 feet on 
August 23, 1901 ; the range observed in 1902 was much less, viz., 13'5 
from the surface to a depth of 100 feet. Down to a depth of 25 feet the 
readings were higher in 1901 than in 1902, but beyond that depth the 
temperature was lower in 1901 than in 1902. The greatest fall of 
temperature was observed between the depths of 25 and 40 feet in both 
seasons, but the decrease of temperature within this interval of 15 feet 
amounted in 1901 to 13-3 and 13-4, while in 1902 it amounted only to 
8. The only observations that may be compared, as regards range 
of temperature, with these in Loch Achilty, were taken in Loch Mon- 
zievaird* in the Tay basin on June 8, 1903, when the range amounted 
to 20 0< 6 from the surface to a depth of 36 feet, and when a fall of 
temperature equal to l-5 per foot of depth was'observed between 5 and 
15 feet. The temperature conditions observed in Loch Achilty (as well 
as in Loch Monzievaird) may probably be ascribed to (1) the com- 
paratively great depth, (2) the comparatively small drainage area, 
and (3) the sheltered position, the thickly wooded shores tending to 
temper the force of the winds blowing across the surface of the water. 
Mention may here be made also of the large range of temperature 
observed in the little Loch Dubhf in the nan Uamh basin on July 12, 
1902, when the range amounted to 15| from the surface to a depth of 
100 feet ; it is possible that under favourable weather conditions, and 
later in the season, the range of temperature in the waters of Loch Dubh 
may equal that observed in Loch Achilty. 



* See p. 120. 



f See p. 255. 



THE FRESH-WATER LOCHS OF SCOTLAND. 277 

Loch Garve (see Plate LXL). Loch Garve lies about 5 miles to the 
west of Strathpeffer, and to the south-west of the mighty Ben Wyvis 
(3295 feet). It receives the drainage from a large tract of mountainous 
country lying to the north and north-west. The body of the loch 
trends in a north-west and south-east direction, and is somewhat 
elliptical in outline, while the south-eastern end takes a slight bend 
to the north-east. The loch is over 1| miles in extreme length, with 
a maximum breadth of .half a mile, the mean breadth being over 
one-third of a mile. Its waters cover an area of about 380 acres, or 
over half a square mile, and it drains an area of 114 square miles an 
area nearly 200 times greater than that of the loch. The maximum 
depth of 105 feet was observed near the centre of the loch, but 
towards the south-western shore. The volume of water is estimated 
at 721 million cubic feet, and the mean depth at 43 J feet. The loch 
forms on the whole a simple basin, with a slight shoaling at the 
position of the bend in the outline of the loch. The 10-feet and 25-feet 
contours extend from end to end of the loch, following approximately 
the form of the shore-line ; but the deeper contours are confined to 
the wide body of the loch, the 50-feet basin being nearly a mile, and 
the 100-feet basin nearly a quarter of a mile, in length. Off the 
central portions of both the north-eastern and south-western shores 
the slope is moderately steep. The longitudinal section A-B on the 
map is taken along the axis of maximum depth, and shows the slight 
deepening of the water near the south-eastern end. The areas between 
the consecutive contour-lines, and the percentages to the total area 
of the loch, are as follows : 

to 25 feet 131 acres 34 '5 per cent. 

25,, 50 104 27-4 

50,, 75 72 18-8 

75,, 100 64 16-9 

Over 100 , 9 , 2-4 



380 , 100-0 



From this table it will be seen that nearly two-thirds of the entire 
lake-floor is covered by less than 50 feet of water. Loch Garve was 
surveyed on August 15, 1902, when the elevation of the lake-surface 
was found to be 218-8 feet above the sea ; when visited by the Ordnanc-3 
Survey officers on August 15, 1871, the elevation was 219*6 feet above 
sea-level. 

Temperature Observations. The following table gives the results of 
observations made in Loch Garve in 1901 by Mr. Clark, and in 1902 
by the Lake Survey : 



278 



BATHYMETRICAL SURVEY OF 



Depth in feet. 


August 18, 1901 
(R. M. Clark). 


August 15, 1902. 




Fahr. 


Fahr. 





59-3 


54-2 


5 


59-3 




10 


59-3 


54 : 2 


15 


59-2 


... 


20 


59-2 




30 


... 


54 : 2 


40 


59-0 




50 




54-0 


55 


55-4 




60 


54-2 


... 


70 ' 


51 -0 


53 : 5 


85 


49-0 





The 1901 observations show a range exceeding 10, whereas the 1902 
observations show that the temperature was practically uniform from 
surface to bottom, which may perhaps be ascribed to the influence 
of the strong winds prevailing at the time of the survey, causing a 
thorough circulation in the whole body of water. 

Loch Kinellan (see Plate LXL). Loch Kinellan is a small shallow 
loch near Strathpeffer, which was surveyed on August 23, 1902. The 
elevation of the lake-surface was not determined by levelling, but 
from the Ordnance Survey contours it is evidently nearly 500 feet 
above the sea. It trends north-east and south-west, widest in the 
south-western portion, and with a large wooded island near the centre. 
Weeds abound along the western and south-western shores, and also 
between the island and the eastern shore. It is one-third of a mile 
in length, and its waters cover an area of about 15 acres. Soundings 
of 10 and 11 feet were taken to the north-east of the island, but the 
deepest part lies to the south-west, the maximum depth of 16 feet 
having been observed about midway between the island and the 
southern shore; 73 per cent, of the lake-floor is covered by less than 
10 feet of water. The volume of water is estimated at 5 million cubic 
feet, and the mean depth at over 7 feet. The temperature of the 
surface water at 12.30 p.m. on the date of the survey was 58-7 
Fahr., and at a depth of 14 feet 58'3. 



Loch Ussie (see Plate LXI.). Loch Ussie (or Usie) is about a mile 
from Strathpeffer and 3 miles from Dingwall. It is irregular and 
subcircular in outline, with a maximum diameter from north-east to 
south-west of nearly a mile. There is one large island with a heronry 
upon it, and several smaller ones, and weeds are abundant in some 
of the bays and in the vicinity of the islands. It was surveyed on 
August 29, 1902, but the elevation above the sea was not determined 



THE FRESH- WATER LOCHS OF SCOTLAND. 279 

by levelling; when visited by the Ordnance Survey officers on Sep- 
tember 7, 1870, the elevation was 418'9 feet above sea-level. Its waters 
cover an area of nearly 200 acres, or less than one-third of a square 
mile, and it drains an area of nearly 4 square miles. The loch is on 
the whole very shallow, with a deep hole in the north-eastern part of 
the loch, in which two soundings of 35 feet were taken; except for a 
neighbouring sounding of 22 feet, the remainder of the lake-floor is 
covered by less than 20 feet of water, and all the western and southern 
parts of the loch are less than 10 feet in depth. The volume of water 
is estimated at 68 million cubic feet, and the mean depth at 8 feet. 
Only 22 per cent, of the lake-bottom is covered by more than 10 feet 
of water, and only 2 per cent, by more than 25 feet of water. At 
5.15 p.m. on the date of the survey the surface temperature was 59'3 
Fahr., and a reading at 27 feet gave 59-0. 

Loch Glass (see Plate LXIL). Loch Glass is one of the larger and 
more important lochs within the drainage basin of the Cromarty firth, 
and it exceeds in depth all the other lochs of the basin. It lies in a 
mountainous district to the north of Strathpeffer, with Ben Wyvis and 
other peaks exceeding 3000 feet in height to the south-west, and lesser 
mountains to west, north, and north-east. It trends in a north-west 
and south-east direction, but with a slight bend in the outline, causing 
it to appear somewhat crescent-shaped. It is 4 miles in length, with a 
maximum width near the centre of two-thirds of a mile, narrowing 
gradually towards the south-east end, where the river Glass flows out, 
the mean breadth being nearly half a mile. Its waters cover an area of 
nearly 2 square miles, and it drains an area exceeding 25 square miles. 
The maximum depth of 365 feet was observed nearer the north-west 
than the south-east end, and towards the north-eastern shore. The 
volume of water is estimated at 8265 millions of cubic feet, and the 
mean depth at 159 feet. It was surveyed on August 26 and 27, 1902, 
but the elevation of the lake-surface above the sea was not determined 
by levelling ; when visited by the Ordnance Survey officers on September 
1, 1868, the elevation was found to be 712*9 feet above sea-level. 

Loch Glass forms a simple basin, with very few minor undulations 
of the lake-floor. The deeper water lies towards the north-west end, 
and the contour-lines all enclose continuous areas. The 100-feet basin 
is 2 1 miles in length, approaching close to the north-west end, but 
distant nearly a mile from the south-east end. The 200-feet basin 
is nearly 2 miles, and the 300-feet basin over a mile, in length, being 
distant respectively 1| and 2 miles from the south-east end. The 
soundings indicate here and there slight irregularities on the lake-floor, 
and sometimes in very deep water. One of these gives rise to a curious 
sinuosity in the 300-feet contour-line off the south-western shore, and 
the sounding immediately to the south-west of the maximum depth of 



280 BATHYMETRICAL SURVEY OF 

365 feet indicates a shoaling of the water to 346 feet, followed by a 
deepening of the water to 354 feet, which is well brought out in the 
cross section C-D on the map. The longitudinal section A-B shows the 
rapid deepening of the water on proceeding from the north-west end, 
and the gradual shoaling of the water on approaching the opposite end 
of the loch. The areas between the consecutive contour-lines, and the 
percentages to the total area of the loch, are as follows : 

to 100 feet 454 acres 38 '1 per cent. 

100,, 200 309 25-8 

200,, 300 ,, 269 22-6 

Over 300 , 161 13'5 



1193 100-0 

The comparatively large area of the lake-floor covered by more than 
300 feet of water indicates the flat-bottomed character of the deeper 
part of the loch, and this is also shown by the comparatively great 
width of the 200-feet and 300-feet basins, and is well seen in the cross 
section C-D. 

Temperature Observations. An interesting series of temperatures 
was taken in the deepest part of Loch Glass at 6 p.m. on August 27, 
1902, as given in the following table: 

Surface 54 C '7 Fahr. 

50 feet 51-7 

100 46-2 

150 43'5 

250 42-5 

350 ... 42-3 

This series shows a range of temperature from surface to bottom 
amounting to 12-4, the greatest fall being one of 5 0> 5 between 50 and 
100 feet. The temperatures taken in Loch Achilty six days earlier gave 
a higher temperature from the surface down to 30 feet than was 
observed at the surface of Loch Glass, but a lower temperature at 50 
and 100 feet, the differences being respectively 5-7 and l-3. 

Loch Morie (see Plate LXIII.). Loch Morie (or Muilie) lies less 
than 2 miles to the north of Loch Glass, with the crests of Meall Beag 
(2121 feet) and Meall Mor (2419 feet) rising between them. It is an 
important and deep loch, containing trout, but the fishing is preserved. 
Lochs a' Chaoruinn and Loch Magharaidh, which flow into it, could 
not be sounded for lack of boats. It trends in a north-west and south- 
east direction, with a slight sinuosity in its outline. It is 2J miles 
in length, with a maximum breadth of over half a mile. Its waters 
cover an area of nearly a square mile, and it receives the drainage from 
a large tract of the mountainous country to the north-west, the area 



THE FRESH- WATER LOCHS OF SCOTLAND. 281 

of which exceeds 35 square miles. The maximum depth of 270 feet 
was observed in the central part of the loch, but nearer the south- 
western than the north-eastern shore, as will be seen in the cross section 
C-D on the map, which is taken at the position of the deepest sounding. 
The volume of water is estimated at 3201 millions of cubic feet, and the 
mean depth at 125 feet. Loch Morie was surveyed on August 28, 1902, 
when the water-surface was found to be 621-6 feet above the sea; when 
visited by the Ordnance Survey officers on September 28, 1868, the 
elevation was 622 feet. The loch forms a simple basin, the contour- 
lines all enclosing continuous areas. The shallower contours follow 
approximately the outline of the loch, but the deeper ones bend in their 
central portions towards the south-western shore. The 100-feet basin 
is over 1J miles, and the 200-feet basin is over a mile, in length. The 
slope of the bottom is in some places very steep for instance, off the 
south-western shore towards the north-west end, where a sounding 
of 75 feet was taken about 60 feet from shore, and one of 124 feet about 
120 feet from shore, showing in each case a gradient exceeding 1 in 1. 
The areas between the consecutive contour-lines, and the percentages to 
the total area of the loch, are as follows : 

Oto 50 feet 148 acres 25 -2 per cent. 

50,, 100 92 15-8 

100,, 150 104 17-7 

150,, 200 113 19-2 

200,, 250 106 18-0 

Over 250 , 24 , 4-1 



587 100-0 



It will be observed that the area between 50 and 100 feet, and to a 
less extent that between 100 and 150 feet, are smaller than the 
shallower and deeper zones, indicating an average slope steeper between 
50 and 150 feet than elsewhere. The temperature of the surface water 
was 54-0 Fahr. on the date of the survey, but serial temperatures could 
not be attempted on account of the gale that was blowing. 

Luck Eye (see Plate LXIV.). Loch Eye is a rather large but very 
shallow loch, about 3 miles from Tain and a mile from Inver bay, an 
inlet of the Dornoch firth. It was surveyed on September 26, 1902, 
when the surface of the water was found to stand 47-8 feet above the 
sea; on December 24, 1867, the Ordnance Survey officers found the 
elevation to be 50*7 feet above sea-level, or 3 feet higher than in 1902. 
The loch is 1J miles in length, with a maximum width of nearly two- 
thirds of a mile, and covers an area of over 210 acres, or one-third 
of a square mile. The maximum depth is 7 feet, and the mean depth 
4 feet, the volume of water being estimated at 37 million cubic feet. 



282 



BATHYMETRICAL SURVEY OF 



Ratio to 
area of 
loch. 



all 

li'S 



t ^H>OO5W'-H QOlT 



3 8 



81 

a~< 

*!l 



tr^* GO ^ ^ O* O 1 00 Oi C^ ^^ *O 'OC 

SCO ^ CC *O C^ 00 ^H CC ^ CO 
OS C^ QO CO l> 



ccc 



'^ 00 CC 00 SO t^* ^O w^ 'Ct' wi' ^O Tt^ iC ^ 1^* O 
IT"* ^ QO CC 00 O^> CC Oi CC CC OC T^ 'C CC OS ^H 
i (M - M- 05 CO CO CO ^H ,-H 1C ^H ^ 



*i 

13 



So S P S S w S S w P o c5 S 5 



111 



09 1** Oft CO 64 ^1 P A 



Q C 



0000000000000000 



t 



OJ t^* i?t t^* "^ ^ ^ *C J O tr^~ "^ cc "^ CC O 

ca T^ \c ip oo cc o: p oo oo ip cc oo o cc 






03^ 



(M O5 O5 
00 6^ 



1 s 
.o 



os^-3> 

o "i * S < x 3 < 5 b S S^s 



THE FRESH- WATER LOCHS OF SCOTLAND. 283 

The loch is a flat-bottomed shallow basin, 45 per cent, of the lake-floor 
being covered by more than 5 feet of water. The temperature of the 
surface water on the date of the survey was 54-8 Fahr., while a 
reading at the bottom in 7 feet gave 55*0. 

The particulars regarding the lochs in the Conon basin are collected 
together in the table on p. 282 for convenience of reference and com- 
parison. From this table it will be seen that in the sixteen lochs under 
consideration, which cover an area of over 11 J square miles, nearly 
2200 soundings were taken, or an average of 188 soundings per square 
mile of surface. The aggregate volume of water contained in the 
lochs is estimated at nearly 30,000 millions of cubic feet, and the 
area draining into them is over 366 square miles, or 31J times the area 
of the lochs. 



NOTES ON THE GEOLOGY OF THE CONON BASIN. 
By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. 

The rock groups entering into the geological structure of the Conon 
basin and the area including Strath Glass and Strath Rusdale, north 
of Ben Wyvis, belong to the crystalline schists and the Old Red 
Sandstone. A line drawn from a point in Strath Rusdale above Ardross 
Castle, south-west by Eileneach in Strath Glass, Achterneed station, 
the Falls of Rogie, and across the Conon to Glen Orrin above Muirtown 
House, roughly marks the boundary between the metamorphic rocks to 
the west and the Old Red Sandstone bordering the Cromarty firth. 
It will thus be seen that the crystalline schists form not only the greater 
part of the basin, but also the highest and wildest territory. 

From the researches of the Geological Survey, extending over the 
greater portion of the area under description, it would appear that the 
metamorphic rocks may be arranged in two divisions : (1) a group of 
acid, basic, and ultrabasic rocks, resembling certain types of Lewisian 
gneiss of pre-Torridonian age along the western seaboard of Sutherland 
and Ross; (2) the Moine series, representing altered sediments and 
including the main subdivisions, (a) granulitic quartz-schists or quartz 
biotite granulites, (b) flaky muscovite biotite schists or gneiss frequently 
garnetiferous, and passing into flaggy mica-schists (pelitic schists). 

Though the group of rocks of Lewisian type comprises certain acid 
granulitic gneisses that closely resemble the quartzose members of the 
Moine series, yet their dominant feature is the alternation of acid and 
basic materials in the form of biotite and hornblende gneisses. With 



284 BATHYMETRICAL SURVEY OP 

these are associated bands of garnet, amphibolite, and hornblende 
schist that have been mapped for some distance both in the Fannich 
mountains and near Scardroy, in the basin of the Meig. In some areas 
schists of the ultra-basic type appear that represent original masses of 
peridotite. This group forms isolated areas or inliers in the midst 
of the Moine series, being regarded as older than the latter, and 
probably representing the floor or platform on which the members of 
the Moine series rest. It is significant that different bands of the 
so-called Lewisian gneisses in the Conon basin are in contact with the 
crystalline Moine schists of sedimentary origin, and that different 
subdivisions of the latter overlap the former. 

These gneisses of Lewisian type appear at intervals, sometimes 
forming comparatively narrow zones, and, again, rather broad belts. 
On the north and west slopes of the Fannich mountains they have been 
traced for several miles, being there overlain and underlain by the 
flaky muscovite biotite schists of the Moine series. Southwards between 
Strath Bran and the basin of the Meig, near Scardroy, there is a large 
development of them, where their relations to the Moine schists are 
well displayed. They likewise appear in Glen Orrin, and southwards 
towards Glen Strathfarrar, and eastwards near Loch Luichart. 

With the exception of certain masses of foliated and unfoliated, 
intrusive, igneous rocks, the members of the Moine series occupy the 
rest of the area covered by the crystalline schists. Their lithological 
characters are comparatively uniform. The two main subdivisions, 
already indicated, graduate into each other in certain localities, thus 
forming an intermediate type between the highly quartzose granulitic 
schists on the one hand and the flaky muscovite biotite schists on the 
other. The members of the Moine series, which have the largest 
development and the widest distribution, consist of granulitic quartz- 
schists or quartz biotite granulites, but the pelitic schists sometimes 
form the most elevated ground, as, for instance, on Sgurr Mor Fannich 
(3637 feet), the highest of the Fannich mountains.* The boundary line 
between the two main subdivisions of the Moine series is highly involved, 
showing intricate rapid folding, frequently isoclinal, and pointing to 
intense reduplication of the strata. The most prominent belts of the 
garnetiferous muscovite schists have a wide distribution in the basin of 
the Conon. For example, they appear in the Fannich mountains, and 
extend south-west by Ben Fionn and Loch Rosque to Moruisg, east of 
Glen Carron. They likewise appear in Glen Orrin and Glen Meig, 
and prominent bands have been traced more or less continuously from 
Strath Bran north-north-west by Aultguish and the hills west of Strath 
Vaich to Glen Beg and Glen Alladale, in the basin of Strath Carron. 



* The quartz-schists contain pebbly bands in places, thus clearly showing their 
derivative origin. 



THE FRESH- WATER LOCHS OF SCOTLAND. 285 

Still further east, this characteristic zone has been followed from Ben 
Wyvis across Strath Glass and Strath Rusdale to the hills near Fearn. 

The constant reappearance, throughout the metamorphic area of the 
Conon basin, of the two main subdivisions of the Moine series suggests 
the repetition of these zones by folding. Indeed, such is the view 
adopted by the Geological Survey, and hence the actual thickness of 
this series may be much more limited than the persistent dip of the 
strata in one direction would lead us to suppose. The researches of the 
Survey indicate a probable order of succession in these schists which 
obtains in the tract between Ben Wyvis and Ben Dearg, and between 
Garve and the Carron that flows into the Dornoch firth. 

In the flaky muscovite biotite schists, and in the quartzose granulites, 
bands of garnet amphibolite and hornblende schists occur, which have 
a wide distribution and are characteristic of certain horizons. 

Reference must now be made to the foliated granite, intrusive in 
the Moine series, which is one of the most interesting features in the 
geology of the Conou basin. Its boundaries are of prime importance, 
because the distribution of the boulders supplies valuable evidence 
regarding the direction of the ice-flow during the glacial period. There 
are two important masses of these older intrusive rocks. The larger 
one extends from Cam nan Aigheinn, near the head of Strath Rannoch, 
north-east by Carn Chuinneag to Cnoc an Liath-bhaid beyond Strath 
Rusdale, and measures about 12 miles in length and about 5 miles in 
breadth. The smaller one stretches from the hills above Loch Luichart 
north-east by Inchbae to Carn More east of Strath Rannoch, being 
about 5 miles long and less than 3 miles broad. Again, on the north 
shore of Loch Luichart there are four outcrops of foliated granite, 
evidently belonging to the same set of intrusions. The Inchbae type 
of augen-gneiss or granite is well known, with large porphyritic crystals 
of orthoclase felspar oriented in a definite direction, enclosed in a 
granulitic ground-mass of quartz, felspar, and micas, together with 
crystals of garnet and sphene. This coarse porphyritic variety is 
largely developed in the Carn Chuinneag mass, where it is associated 
with foliated riebeckite granite or augeii gneiss. Frequently the rock 
is fine grained, and merges into a finely crystalline schist. 

Evidence has been obtained that these older granite masses with 
their basic modifications were intruded into the series of Moine 
sediments before they were converted into crystalline schists. A well- 
marked aureole of contact metamorphism accompanied this intrusion, 
which in places has been obscured by subsequent deformation. But 
at intervals round the margin the sediments are hornfelsed, and still 
show their original bedding-planes, while garnets and crystals of 
andalusite have been developed. It is further apparent that the granite 
masses and the Moine sediments have been subjected to a common series 
of dynamic stresses, for the planes of schistosity in the granite are 



286 BATHYMETRICAL SURVEY OF 

parallel to those in the Moine schists ; indeed, in certain localities they 
pass, irrespective of the boundary-line, from the igneous to the altered 
sedimentary rocks. 

On either side of the Sutors of Cromarty, and stretching southwards 
along the sea-cliff to Fortrose, there is a narrow belt of crystalline schists 
rising from underneath the Old Red Sandstone. They belong to the 
group of quartz biotite granulites, and are associated with bands of 
amphibolite. 

Newer granite masses are also represented in the area, as, for 
instance, on the hills north of Ardross Castle above Strath Rusdale, 
and in Glen Orrin west of Fairburn House. They resemble the normal 
types of the newer granite masses of the Highlands, and were erupted 
after the Moine schists had assumed their present crystalline character. 

The strata of Old Red Sandstone age in the basin of the Cromarty 
firth are arranged in the form of a great syncline, whose axis runs in a 
north-north-east and south-south-west direction. The base of the series 
and the order of succession are admirably displayed on the sea-cliffs at 
Cromarty, and on the south-east shore of that firth as described long 
ago by Hugh Miller. The basal conglomerate is there overlain by the 
well-known fish-band, with calcareous nodules, graduating upwards 
into the coarse sandstones that form the centre of the basin. On the 
west side of the firth a similar sequence is observable. The basal con- 
glomerate along the flanks of the hills is usually brought into conjunction 
with the crystalline schists by a fault, evidently of no great amount, for 
the unconformity is visible at certain localities. This horizon is sur- 
mounted by red sandstones and flagstones, calcareous and bituminous 
shales, and occasional intercalations of clays with limestone nodules, 
with fish remains. These are followed by an upper band of conglomerate, 
which is overlain by the coarse sandstones in the centre of the basin. 

Various outliers of Old Red Sandstone, largely composed of con- 
glomerate, and resting unconformably on the highly denuded platform 
of crystalline schists, occur some miles to the west of the main area of 
this formation in the Conon basin. Some of these are met with on the 
plateau between Loch Luichart and Aultguish. By far the largest and 
most important is that still further north in Strath Vaich, where an 
extremely coarse conglomerate, composed largely of blocks of the 
contiguous foliated granite, is found on the crest of Meall a' Ghrianain 
(2531 feet). 

At the base of the sea-cliff formed by the crystalline schists and Old 
Red Sandstone of the Black Isle and the North Sutor, there are small 
patches of Oolitic rocks which have only a limited development. They 
occur on the beach below high-water mark at Eathie and at Port-an- 
Righ and Cadh-an-Righ near Sandwick. By means of the great fault 
that traverses the line of the Caledonian Canal, and is continued 
north-east along the shore of the Black Isle, these Secondary strata 
have been let down against the older rocks. 



THE FRESH- WATER LOCHS OF SCOTLAND. 287 

Regarding the lines of displacement in the Conon basin, one of the 
most important is that just referred to, which skirts the base of the Black 
Isle, and is prolonged north-east to Tarbat Ness, whereby this straight 
feature has been determined. The great fault that traverses Loch 
Maree and Glen Docharty passes south-east by Ledgown, thence across 
the watershed by Carn Chaorainn to Loch Beannachan in the basin if 
the Meig. Another powerful dislocation, nearly at right angles to the 
course of the Loch Maree fault, has determined the north-north-east 
direction of the Meig valley between Inbhir-Chaorainn and Milton 
of Strathconon, and stretches south-west up Glen Chaorainn in the 
direction of Loch Monar, and north-north-east to the head of Loch 
Luichart. 

During the period of extreme glaciation it would appear that the 
ice-shed lay some distance to the east of the existing watershed in part 
of the Conon basin, for boulders of foliated granite or augen gneiss, 
from one or other of the masses near Inchbae, have been carried west- 
ward into the valley of Loch Broom, to Inverlael, and nearly as far as 
Ullapool. Their distribution in an eastward direction is no less 
remarkable, for they have been traced as erratics across the Black 
Isle and the Moray firth to the plain of Moray and the low grounds of 
Banff shire. The boulder clay of the north part of the Black Isle 
contains numerous blocks of this well-known rock, which were probably 
dispersed during the greatest extension of the ice. Such evidence is in 
harmony with that obtained in the Assynt district, where blocks of the 
eastern schists have been carried from the plateau of the Moine schists, 
east of the existing watershed, to higher elevations to the west, formed 
of Cambrian strata. In view of these facts, it seems probable that 
during one stage of the glacial period the Conon basin must have been 
buried under an ice-sheet that overtopped the highest hills, the move- 
ment of which was largely independent of the physical features of the 
region. 

During the period of confluent glaciers that ensued, the great 
mountain groups formed more or less independent centres of dispersion. 
Indeed, many of the striae, the disposition of the moraines, and the 
distribution of the carried blocks furnish evidence relating to this 
phase of glaciation. In the Fannich mountains a range running east 
and west for about 7 miles, and whose main peaks rise above 3000 feet 
ice-markings were found on the southern slopes at elevations between 
2250 and 2500 feet trending south-south-east. Striae pointing in a 
similar direction occur at various points on the ridge between Loch 
Fannich and Strath Bran, thus showing that at one period the Fannich 
ice must have crossed that loch into the Bran valley. Again, during 
this later glaciation, ice crossed the watersheds from Glen Fhiodaig 
and from Strath Conon into the valley of the Bran, and after uniting 
with the glaciers from Fannich and the Blackwater, passed eastwards 



288 BATHYMETRICAL SURVEY OF 

by the Conon valley towards the Black Isle. The striae, trending about 
east-south-east, found on the tops of Meall na Speirag and Beinn Liath 
Beag at elevations of about 2000 feet, on the watershed between the 
Blackwater and the streams flowing into Loch Luichart, clearly show 
the development of the ice during this period. 

Important evidence regarding the transport of materials during the 
time of the confluent glaciers is furnished by the distribution of boulders 
of foliated granite and Old Red Sandstone on the slopes of Ben Wyvis. 
These have been carried from the west or west-north-west, and have 
been traced up to a height of 2400 feet on Cam Gorm and Little Wyvis, 
while their upper limit on Ben Wyvis itself is 2300 feet. It is further 
apparent that the ice moved through the pass between Little Wyvis and 
An Cabar, and streamed down the valley of Loch Glass north of Ben 
Wyvis. Still further north in Kildermorie forest and Strath Rusdale, 
the direction of the ice-flow was south of east, as proved by the striae, 
and the transport of boulders of foliated granite or augen gneiss. From 
the period of confluent glaciers to the time of their disappearance in 
the upland glens, the various stages of retrocession are represented by 
the moraines. 

Loch Fannich. The soundings clearly show that this lake gradually 
deepens towards the eastern portion, the deepest sounding, 282 feet, 
being situated about a mile above the outlet. The hill-slopes on both 
sides of the loch for considerable distances are covered with morainic 
drift, save near the outlet, where there is a prominent barrier of rock. 
At the latter point the southern spur of An Coileachan approaches the 
northern margin of the lake, and is prolonged on the south side in An 
Cabhar and Carn na Beiste. Along the eastern side of this ridge, the 
quartzose granulites and muscovite biotite schists are isoclinally folded 
on vertical axes striking north and south that is, at right angles to 
the course of the lower part of the loch. At the outlet, and for a mile 
below that point, the Grudie river flows on alluvial deposits, these 
materials having been largely contributed by side streams, and especially 
by Allt a' Choin Idir, draining from the north. Beyond the alluvium, 
at the 800-feet level, the Moine schists are exposed in the bed of the 
river and on the hill-slopes, and there is here no indication of a pre- 
glacial river channel filled with drift. The surface of Loch Fannich is 
822 feet above Ordnance datum, so that the depth of the rock basin 
below the rocky barrier, visible about a mile beyond the outlet, is 
260 feet. 

Loch Luichart. This lake is a true rock basin lying among the 
crystalline schists, with a barrier formed of these materials at its outlet. 
Where the stream issues from the loch, it runs through a narrow gorge 
of rock and over successive waterfalls. In this sheet of water there are 
three basins, of which the most westerly is the most important, its 
greatest depth being 164 feet. The surface of the lake is 250 feet above 



THE FRESH-WATER LOCHS OF SCOTLAND. 289 

Ordnance datum line. The axis of the upper part of the loch coincides 
with the strike of the crystalline schists, while that of the lower is 
obliquely across it. It is interesting to note that the deepest basin has 
been excavated out of the flaky muscovite biotite schists, while the 
shallow part about the middle of the loch north of Creag Mhor cor- 
responds with a belt of highly siliceous Moine schists folded over a core 
of gneiss of Lewisian type. The head of the lake nearly coincides with 
the Strath Conon fault already referred to, which crosses the lake in 
a north-north-east direction, and has there produced considerable 
brecciation of the strata. Only a small part has been silted up at the 
western end by the alluvial material brought down by the Bran and 
the Grudie. 

Loch a' ('liroixy and Loch Crann. The former lake is evidently a 
rock basin, for, though at its outlet it flows over alluvial deposits that 
mark the site of an old lake, the rocky barrier appears about 2 miles 
east of Achnasheen, where the 400-feet contour-line crosses the Bran 
river. The surface of the loch is 508 feet above Ordnance datum, and 
the deepest sounding is 168 feet, so that the depth of the loch below the 
rocky barrier beyond Achnasheen is 60 feet. Loch Crann has been 
separated from Loch a' Chroisg by a cone of alluvium brought down by 
the streams on both sides of the valley at that point. 

Loch Aduinalt and Loch a' ChuiUtui represent the remains of a lake 
which once extended for 4 miles up the valley to Dosmuckeran, the level 
of which has been lowered by the Bran. The materials cut through 
during this process of denudation consisted of moraine matter, but the 
river has now reached the solid rock. The terraces round Loch Achanalt 
and Loch a' Chuilinn rise to a height of 20 feet above the surface of 
these sheets of water. The deepest sounding in the former is 9 feet, and 
in the latter 43 feet. While Loch Achanalt is being rapidly silted up 
by alluvial detritus, Loch a' Chuilinn preserves its character of a rock 
basin. At its outlet the water flows over an ice-moulded surface of 
granulitic quartzose schist. The strike of the strata is nearly parallel 
with the long axis of the loch. 

Loch Beannachan. As already indicated, this lake lies along the 
line of the powerful fault that has been traced in a south-east direction 
from Loch Maree and Glen Docherty. 

Loch Garve is evidently the remnant of a much larger sheet of water 
that formerly extended from Little Garve down to the Falls of Rogie 
a distance of about 4 miles. The former level of the lake has been 
lowered by the erosion of the drift deposits and the cutting of the rock 
gorge at the Falls of Rogie. The surface of the present loch is 220 feet 
above Ordnance datum line, and the deepest sounding is 105 feet. The 
200-feet contour-line crosses the stream at these waterfalls. Hence, 
on the assumption that the Moine schists and epidiorite sills exposed at 



290 BATHYMETRICAL SURVEY OF 

the latter locality formed the original rocky barrier of the lake, the 
depth of water below this level in Loch Garve is still 84 feet. 

Loch Achilty. Though this lake is small, its extreme depth (119 
feet) is remarkable. There is no proof that it occupies a rock basin, but 
it is not improbable that such may partly be the case. Towards the 
east it has been filled in by the delta gravels of the Blackwater, and 
on the other side by those of the Conon at the time of the formation 
of the 100-feet beach. 

Loch Ussie is a shallow basin, 35 feet in depth, resting in drift ; and 
Loch Kinellan appears to be banked by superficial deposits at the west 
end, while at its eastern margin the bituminous shales of the Old Red 
Sandstone are exposed. Its greatest depth is only 16 feet. 

Loch Morie is obliquely traversed by a line of fault, with a down- 
throw towards the south-west, that branches westwards in the upper 
part of the basin. Each branch shifts the outcrop of the zone of 
altered strata in contact with the mass of foliated granite already 
referred to. The stream issuing from the' lake flows over a rocky barrier, 
but it is possible that there may have been a former outlet now concealed 
by drift. 

Loch Glass. Round the north-east margin there are traces of 
terraces between Culzie Lodge and the foot of the lake. No rocky 
barrier appears till the Falls of Eillenach are reached, where the stream 
flows over a mass of conglomerate of Old -Red Sandstone age at an 
elevation of about 680 feet. As the surface of the loch is 713 feet above 
Ordnance datum line, and the deepest sounding is 365 feet, it follows 
that the depth of water in Loch Glass below the level of the barrier at 
the Falls of Eillenach is 332 feet. 

Loch Eye lies on the stratified deposits of the 100-feet beach. 



NOTES ON THE BIOLOGY OF THE LOCHS IN THE CONON BASIN. 
By JAMES MUREAY. 

The lochs of the Conon basin, with the exception of Loch Eye, which 
will be separately noticed, have the plankton of a very uniform 
character. The fauna includes only those species which are common 
to the whole country, and calls for little detailed notice. The most 
important feature in it is the .total absence of all those species of 
Diaptomus (D. Wierzejskii, D. laticeps, D. laciniatus) which are 
common in the districts to the north and south of the Conon valley. 
This valley, extending nearly across Scotland, forms a line of inter- 
ruption in the distribution of those species, a line completed towards 
the west by Lochs Maree, Dhugaill, and Sgamhain, all of similar 



THE FRESH- WATER LOCHS OF SCOTLAND. 291 

character. Any slight peculiarity in the fauna will be noted under the 
name of each loch. 

In contradistinction to the absence of western species in the fauna of 
these lochs, is the occurrence in the flora of several Desmids of the 
western type. These western Desmids, though less numerous than in 
districts both to the north and south, are in most of the lochs. 

Loch Gown, North and South. These very shallow basins had an 
admixture of littoral species in the plankton, and the numerous 
Desmids included both pelagic and bog species. 

Loch a' Chroisg. The only peculiarities of this loch were the 
abundance of algae and of the smaller pelagic animals, such as Rotifera 
and Protozoa. Floscularia pelagica, Rousselet, was abundant. 

Loch Achanalt. Owing to its shallow weedy character, littoral 
species were more numerous than pelagic ones. A species of Gammarus 
was of a bright slaty blue colour. Ophridium was abundant on the 
weeds. 

Loch a' Chuilinn. Among the Rotifera observed were Euchlanis 
lyra, E. dilatata, and Plcesoma truncatum. The Desmid Staurastrum 
arctiscon was frequent. 

Loch Fannich. As in most of our largest lakes, there were skeletons 
of ClathruUna elegans floating in the water. Although this is not a 
true plankton organism (it lives attached by a stalk to plants), the 
skeletons have seldom or never been observed during the Lake Survey 
work except in large lakes, while it has rarely been seen living at the 
margins of those lakes. The lightness of the skeletons, enabling them 
to float on fresh water, may serve for the distribution of the species, and 
small cysts are commonly seen in them. Granting this, their absence 
from smaller lakes is- still unexplained. The only suggestion I can offer 
is that the lower specific gravity, resulting from the higher temperature 
of smaller lakes, may prevent the floating of the skeletons, or that the 
higher temperature may lead to a more rapid decomposition of the 
material of which they are composed, and so prevent their accumulation 
in the water. 

Loch Garve. There was nothing peculiar in the plankton, except 
the apparent absence of Desmids. 

Loch Luichart. In contrast with the neighbouring Loch Garve, 
Desmids were here abundant, and other algae were also numerous. 

Loch Achilty. Desmids were numerous, including, among species 
of the western type, Staurastrum arctiscon and S. jaculiferum. 

Loch Kinellan. Ceratium Jiirundinella was very abundant, of a 
form with long divergent middle horns. There were also observed 
Volvox globator, Asterionella with very short rays, a species of Cerio- 
daphnia, and a few larvae of Corethra. 

Loch Uxsie. Ceratium hirundinella, of the same form as in Loch 
Kinellan, was the most abundant organism. This was the only loch in 
the district in which Latona setifera was seen. 



292 BATHYMETRICAL SURVEY OF 

Lochs Glass and Morie have no peculiarity worthy of remark, 
except the much greater abundance of algae in Loch Glass. 

Loch Eye. This loch, which is only considered along with the Conon 
lochs as a matter of convenience, really approximates biologically to 
the lochs of the Shin basin, and of Sutherland generally. It is remark- 
able for the abundance of Diaptomus Wierzejskii, this being the most 
southern locality on the mainland where the type of the species has been 
observed by the Lake Survey, though it extends much further south 
in the Outer Hebrides, where Dr. Scott got it in Barra. The Rotifer 
Triarthra longiseta was also abundant. 



THE FRESH- WATER LOCHS OF SCOTLAND. 293 



LOCHS OF THE SHIN BASIN. 

THE lochs visited by the Lake Survey draining by the river Shin and 
river Oykell into the Dornoch firth are Lochs Shin, Merkland, a' 
Ghriama, Fiodhaig, Gorm Loch Mor, Ailsh, Craggie, an Daimh, 
Migdale, and an Lagain, and it has been found convenient to include 
also Loch Buidhe, flowing by the river Fleet into Loch Fleet, lying to 
the north of the Dornoch firth. The drainage area, to be dealt with is 
indicated on the index map (Fig. 48), and extends from Tarbat Ness 
on the east to Cnoc a' Choilich (little more than 3 miles from the shores 
of Loch Broom) on the west, and to Ben Hee and Carn Dearg on the 
north, the total area being about 860 square miles, of which about 770 
square miles drain into the Dornoch firth and about 90 square miles 
into Loch Fleet. Of this total about 240 square miles drain into 
the lochs under consideration, as will be seen from the summary 
table on page 305. The principal loch is Loch Shin, one of the 
largest of Scottish lochs, the others being comparatively small, Loch 
Merkland being the only one exceeding 2 miles in length. Loch 
Shin receives the outflow from Lochs Merkland and a' Ghriama at 
its northern end, and the outflow from Loch Fiodhaig about 5 miles 
down on its eastern shore. Gorm Loch Mor lies at the headwaters of 
the river Cassley, a tributary of the river Oykell, and Loch an Daimh 
flows by the river Einig into the river Oykell, which also receives the 
outflow from Lochs Ailsh and Craggie. The river Shin, bearing the 
outflow from Loch Shin, joins the river Oykell to form the Kyle of 
Sutherland at the head of the Dornoch firth. Loch Migdale flows by 
a short stream into the Dornoch firth on its northern side, and Loch an 
Lagain flows by a longer stream (the river Evelix) also into the Dornoch 
firth on its northern side. Loch Buidhe flows by the river Torboll into 
the river Fleet at the head of Loch Fleet. The boundary-line between 
Ross-shire and Sutherlandshire follows the course of the river Oykell 
from the head of the Dornoch firth to Breabag Tarsuinn, passing up the 
middle of Loch Ailsh, which thus lies partly in Ross and partly in 
Sutherland, while Lochs Craggie and an Daimh are located in Ross- 
shire and the remaining lochs under consideration in Sutherlandshire. 

Loch Shin (See Plates LXV. and LXVI.). Loch Shin is the largest 
loch in Scotland to the north of Loch Ness, and, as regards length, it 



294 BATHYMETRICAL SURVEY OF 

ranks fifth of all Scottish lochs, being exceeded in this respect only 
by Lochs Awe, Ness, Lomond, and Shiel. It is a fine sheet of water 
situated amid beautiful scenery, with Ben More Assynt and Coniveall 
rising to heights exceeding 3200 feet on the west, and Meall an Eoin 
(3154 feet) on the north-east. It is a good trout loch, containing also 
Salmo ferox, and the islands are much frequented by wildfowl. It 
trends in a north-west and south-east direction, and the length measured 
along the centre of the loch is about 17^ miles. The loch is on the 
whole very narrow, the maximum breadth exceeding 1 mile at the 
junction with the small arm leading to Loch a' Bhainbh, and also at 
the position of the delta formation at the mouth of the river Fiodhaig. 
Elsewhere the breadth is considerably less than a mile, and the upper 
portion, to the north-west of the entrance of the river Fiodhaig, is all 
less than half a mile in width. The mean breadth of the entire loch is 
half a mile, or only 3 per cent, of the length a percentage smaller than 
has been observed in any other large loch except Loch Shiel. * The 
waters of Loch Shin cover an area of about 5570 acres, or nearly 8| 
square miles, and the area of land draining into it is over 150 square 
miles, but as it receives the outflow from Lochs Merkland, a' Ghriama, 
and Fiodhaig, its total drainage area is over 190 square miles an area 
22 times greater than that of the loch. Over 800 soundings were taken, 
the maximum depth recorded being 162 feet, about 7 miles from the 
foot of the loch, opposite the little Loch an Fhreiceadain on the north- 
eastern shore. The volume of water contained in the loch is estimated at 
12,380 millions of cubic feet, and the mean depth at 51 feet, or 31J per 
cent, of the maximum depth. Loch Shin was surveyed on August 25 to 
September 1, 1902, when the elevation of the lake-surface above the sea 
was determined, by levelling from bench-mark, as being 270'85 feet; 
when levelled by the officers of the Ordnance Survey on August 4, 1870, 
the elevation was found to be 269-7 feet above sea-level. The farmer at 
Overscaig stated that the water might fall 1 foot below, and rise 6 feet 
above, the level at the time of the survey. 

The floor of Loch Shin is very irregular. None of the contour-lines 
are continuous from end to end of the loch, and the lines themselves 
are usually of a sinuous character. The 25-feet contour encloses two 
areas, the 50-feet contour three areas, the 100-feet contour four areas, 
and the 1 50-feet contour two areas. The lower 25-feet basin is nearly 
10 miles in length, extending from close to the lower end of the loch 
as far as the alluvial cone at the mouth of the river Fiodhaig. Here 
for an interval of nearly half a mile the soundings indicate depths less 
than 20 feet, except for an isolated sounding of 25 feet towards the 
north-eastern shore. The upper 25-feet basin is nearly 6 miles in 
length, approaching to within half a mile from the head of the loch. 

* See p. 242. 



THE FRESH-WATER LOCHS OF SCOTLAND. 



295 



The lower 50-feet basin is about 8 miles in length, extending from 
within a quarter of a mile from the southern end as far as the entrance 
of the Allt a' Chairr Bhig. Separated from this lower basin by an 
interval of more than half a mile there is a second small 50-feet basin 
based upon soundings of 60, 70, and 80 feet. Proceeding up the loch 
from this small basin there is an interval of nearly 3 miles before 




01 2345 



' English Miles 



FIG. 48. INDEX MAP OF THE SHIN BASIN. 



meeting with the upper 50-feet basin, which is 3J miles in length, and 
approaches to within three-quarters of a mile from the head of the loch. 
The lower 100 -feet basin lies about 2 miles from the foot of the 
loch, and is about 2 miles in length ; the maximum depth recorded in 
this basin was 140 feet, observed in two different places. Separated 
from this lower basin by an interval of 1^ miles lies the central 100-feet 
basin, enclosing the deepest part of the loch, which is about 2 miles 
in length. The remaining two small 100-feet basins are situated 
towards the head of the loch, the larger, distant about l\ miles from 
the head, being 1 mile in length, and having a maximum depth of 
129 feet, separated by an interval of half a mile from the smaller, based 



296 BATHYMETRICAL SURVEY OF 

upon soundings of 104, 106, and 108 feet. Within the central 100-feet 
basin above mentioned the bottom sinks in two places below the depth 
of 150 feet (1) at the south-eastern end of the 100-feet basin, where 
soundings of 156 and 157 feet were recorded; and (2) about half a 
mile farther up the loch and towards the north-eastern shore, where 
the deepest sounding in the loch (162 feet) was taken apparently a 
deep hole surrounded by much shallower water. A section across the 
loch at the position of the deepest sounding is shown in cross-section 
E-F on Plate LXVL, and similar sections are shown in cross-section 
C-D on Plate LXV. taken towards the head of the loch, and in cross- 
section G-H on Plate LXVI. taken towards the foot of the loch. In 
these three sections the deepest part of the loch is seen to lie nearer to 
the north-eastern than to the south-western shore, but this disposition 
does not hold good throughout the loch, for in some of the other lines 
of soundings the deepest casts were taken towards the south-western 
shore. The longitudinal section A-B, placed at the foot of the two 
maps, taken along the axis of maximum depth from end to end of the 
loch, shows how irregular the lake-floor is along this central line, and 
many of the lines of soundings indicate undulations more or less 
pronounced, some of which give rise to striking sinuosities in the 
contour-lines, while others do not affect the contours, or only slightly, 
and are therefore not so easily remarked. As a rule, shallow water 
is found offshore, but occasionally deep soundings were taken close 
inshore for instance, off the small promontory on the north-eastern 
shore, 1J miles from the head of the loch, a sounding of 36 feet was 
recorded ; farther down the same shore, off the mouth of the an Garbh- 
allt, a sounding of 57 feet was taken ; near the pier at Shiness quarry 
on the same shore depths of 32 and 40 feet were found ; and along the 
opposite shore towards the foot of the loch depths of 32, 36, 37, and 
38 feet were found here and there inshore. 

The alluvial cone at the mouth of the river Fiodhaig has already 
been referred to, and here shallow water extends right across the loch, 
cutting it into two deeper portions. The land has been cut into 'a 
delta-shaped form at the head of the loch, where the river from Loch 
a' Ghriama flows into Loch Shin. 

The areas between the consecutive contour-lines at equal intervals, 
and the percentages to the total area of the loch, are as follows : 

to 50 feet 3260 acres 58 '5 per cent. 

50,, 100 ,, 1480 ,, 26-6 

100,, 150 814 ,, 146 
Over 150 , 14 0'3 



5568 . 1000 



These figures show that Loch Shin is comparatively shallow, 58 per 



THE FRESH -WATER LOCHS OF SCOTLAND. 



297 



cent, of the lake-floor being covered by less than 50 feet of water, and 
85 per cent, by less than 100 feet of water, while the area deeper than 
150 feet is exceedingly small. 

Temperature Observations. Numerous surface temperatures were 
taken during the week spent on the survey of Loch Shin, the readings 
ranging from 56-0 Fahr. to 59 0> 0. Three serial temperatures were 
taken, with the following results : 



Depth in feet. 


August 27, 1902, 
5.15 p.m. 


August 30, 1902, 
6 p.m. 


September 1, 1902, 
5.30 p.m. 




Fahr. 


Fahr. 


Fahr. 





56-5 


56-7 


57-0 


2o 




56-1 


56-8 


50 


.-><;< 


56-0 


56-6 


90 




56-0 




100 


54-2 






130 


51*2 







These observations show that the whole body of water down to a 
depth of 90 feet was practically uniform in temperature, but in the 
deepest part of the loch a fall of temperature amounting to 3 was 
observed between 100 and 150 feet. The extreme range of temperature 
from surface to bottom and from end to end of the loch amounted to 
only 7-8. 

Loch Merkland (see Plate LXVII.). Loch Merkland lies about 3 
miles to the north of the head of Loch Shin, amid beautiful surroundings, 
Ben Hee rising to a height of 2864 feet on the north-east, with Cam 
Dearg (2613 feet) and other heights to the north, and Ben Leoid (2579 
feet) to the west. It trends in a north-north- west and south-south-east 
direction, and is 3 miles in length, with a maximum breadth of over 
one-third of a mile, the mean breadth being a quarter of a mile. Its 
waters cover an area of about 440 acres, or two-thirds of a square mile, 
and it drains an area of about 16 square miles. Nearly 120 soundings 
were taken, the maximum depth of 85 feet having been observed close 
to the narrows towards the head of the loch. The volume of water is 
estimated at 577 million cubic feet, and the mean depth at over 30 feet. 
The loch was surveyed on September 2, 1902, when the elevation of the 
lake-surface above the sea was found to be 360-2 feet. 

Loch Merkland is comparatively simple in conformation ; the deeper 
water occurs towards the head of the loch, and is cut into two portions 
by a shoaling of the bottom at the narrow portion where the large 
alluvial cone laid down at the mouth of the Allt nan Allbannach on the 
north-eastern shore approaches the smaller cone at the mouth of the 
Garbh Allt on the opposite shore. The depth of the channel at the 
narrows referred to is 31 feet, and the 10-feet and 25-feet basins extend 



298 BATHYMETRICAL SURVEY OF 

from end to end, roughly approximating with the outline of the loch. 
The principal 50-feet basin extends from the narrows for a distance of 
three-quarters of a mile down the loch, and there is an isolated sounding 
of 52 feet to the north-west of the narrows. The 75-feet basin is a long 
and narrow area, half a mile in length, the deepest sounding having 
been recorded at the upper end of this basin, and comparatively close to 
the south-western shore, off which the slope is steep. This is well shown 
in the cross-section E-F on the map, and at other places along both 
shores the soundings indicate steep slopes. The longitudinal section 
A-B shows the shoaling of the water at the narrows, deepening 
immediately to the south-east to the maximum depth of the loch; 
there is also a scarcely perceptible shoaling farther down the loch, 
where a sounding of 37 feet was recorded, with 47 feet to the north- 
west and 41 feet to the south-east. The areas between the consecutive 
contour-lines, and the percentages to the total area of the loch, are 
as follows : 

to 25 feet 190 acres 43 per cent. 

25,, 50 198 45 

50 75 37 9 

Over 75 14 3 

439 100 

These figures show that the average slope is slightly steeper within 
the 25-feet line than between 25 and 50 feet, and they also show how 
circumscribed is the area deeper than 50 feet, 88 per cent, of the lake- 
floor being covered with less than 50 feet of water. 

Temperature Observations. A series of temperatures taken in the 
deepest part of the loch at 6 p.m. on the date of the survey gave the 
following results : 

Surface 56'8 Fahr. 

25 feet 56'2 

50 , 56-0 

80 ' ... 55'8 ,, 

These observations indicate a range of only 1 from surface to 
bottom. 

Loch a' Ghriama (see Plate LXVIL). Loch a' Ghriama (or Griam) 
lies immediately to the north of the head of Loch Shin, into which its 
waters are carried by a short rapid stream. The distance between the 
two lochs is only a quarter of a mile, and at the time of the survey 
there was a difference in level of nearly 33 feet. It is a good trout 
loch, and Salmo feroz is also found in it. The principal feeder is the 
Amhainn an Ceardaich, over a mile in length, bearing the outflow 
from Loch Merkland. It trends almost north and south, and is 1J 






THE FRESH- WATER LOCHS OF SCOTLAND. 299 

miles in length, nearly uniform in width, the maximum breadth being 
over a third of a mile, and the mean breadth over a quarter of a mile. 
Its waters cover an area of about 260 acres, and it drains directly an 
area of over 6^ square miles; but since it receives the outflow from 
Loch Merkland, its total drainage area is over 22| square miles an 
area 57 times greater than that of the loch. The maximum depth 
of 64 feet was observed approximately in the centre of the loch, 
but rather nearer the northern than the southern end. The volume 
of water is estimated at 314 million cubic feet, and the mean depth 
at 28 feet. The loch was surveyed on September 1, 1902, when the 
elevation of the lake-surface above the sea was found to be 303*7 feet, 
which is almost identical with the elevation observed by the Ordnance 
Survey officers on July 4, 1856, viz. 303-5 feet. 

The conformation of Loch a' Ghriama is simple, with one or two 
very slight undulations of the lake-floor, the principal of which gives 
rise to a striking sinuosity in the 50-feet contour ; otherwise the contour- 
lines coincide approximately with the outline of the loch. The 25-feet 
basin is about 1J miles, and the 50-feet basin over half a mile, in length. 
The longitudinal section C-D, and the cross section G-H taken at the 
position of the deepest sounding, show generally a gradual slope down 
to the greatest depth, and this is borne out by the following table, 
giving the areas between the contour-lines and the percentages to the 
total area of the loch : 

to 25 feet 121 acres 47 per cent. 

25 50 106 41 

Over 50 30 12 

257 .. 100 



Temperature Observations. The following series of temperatures, 
taken at 3 p.m. on September 1, 1902, in the deepest part of Loch a' 
Ghriama, indicates a range of only 2 from surface to bottom : 

Surface 57'OFahr. 

25 feet 56'2 

55 ... / 55-0 

Loch Fiodhaig (see Plate LXVIIL). Loch Fiodhaig (or Fiodiag, or 
Fiag) lies to the north-east of the head of Loch Shin, into which its 
superfluent waters are carried by the river Fiodhaig (or Fiag). This is 
a good trout loch, but the fishing is preserved, surrounded by moorland 
hills, with Ben Hee rising to the north. It receives the outflow from 
Loch a' Ghorm-Choire and another smaller loch lying to the north, 
which were not sounded. The loch trends in a north and south 
direction, and is over 1^ miles in length, with a maximum breadth 
near the northern end of two-thirds of a mile. Its waters cover an 



300 BATHYMETRICAL SURVEY OF 

area of about 370 acres, or over half a square mile, and an area twenty 
times greater an area of over 11 \ square miles drains into it. The 
maximum depth of 71 feet was observed not far from the largest island 
in the loch, and nearer the northern than the southern end. The 
volume of water is estimated at 415 million cubic feet, and the mean 
depth at nearly 26 feet. Loch Fiodhaig was surveyed on October 23, 
1902, but the elevation above the sea was not determined by levelling; 
judging from the contour-lines, the lake-surface is apparently nearly 
700 feet above sea-level. The loch is irregular both in outline and 
conformation. The lake-floor shows undulations, and in some places 
deep water approaches very close to the shore, as may be seen in the 
two sections on the map. The areas between the contour-lines, and 
the percentages to the total area of the loch, are as follows : 

bo 25 feet 203 acres 55 per cent. 

25,, 50 133 36 

Over 50 , 33 , 9 



369 ,, 100 



The temperature of the surface water on the date of the survey was 
48-0 Fahr. 

Gorm Loch Mor (see Plate LXIX.). Gorm Loch Mor lies about 
4 miles to the west of the head of Loch Shin, in a mountainous district, 
with Beinn Leoid (2597 feet) to the north, Beinn Uidhe (2384 feet) to 
the west, and Ben More Assynt (3273 feet) and Coniveall (3234 feet) to 
the south. Its outflow is carried through a series of smaller lochs 
(Fionn Loch Mor, Fionn Loch Beag, and Loch na Sroine Luime), which 
could not be sounded, into the river Cassley. Though a comparatively 
small loch, it has the distinction of being deeper than the other lochs 
in the basin, except Loch Shin. It is very irregular in outline, and 
includes many islands. The length of the loch, along a straight line 
from north-west to south-east, is slightly over a mile ; but along a 
line following the deeper water it is considerably more. The greatest 
width in a north-and-south direction is over half a mile, the mean 
breadth of the entire loch being less than a quarter of a mile. Its 
waters cover an area of about 185 acres, or over a quarter of a square 
mile, and it drains an area of 5J square miles. Nearly 70 soundings 
were taken, the maximum depth of 91 feet being observed comparatively 
close to the western shore. The volume of water is estimated at 196 
million cubic feet, and the mean depth at over 24 feet. The loch was 
surveyed on October 22, 1902, when the elevation of the lake-surface 
was found to be 847*0 feet above the sea ; when visited by the Ordnance 
Survey officers on October 1, 1870, the elevation was 846-4 feet above 
sea-level. 



THE FRESH- WATER LOCHS OF SCOTLAND. 301 

The floor of Gorm Loch M6r is most irregular, islands and banks 
and deep soundings being found here and there in close proximity, 
while in other places deep water approaches close to the shore. The 
contour-lines are of the most sinuous description, with isolated deep 
and shallow patches. The deepest part of the loch runs along the 
western shore, off which the slope is uniformly rather steep, and occurs 
towards the north-western end, as will be seen in the longitudinal 
section A-B on the map. The areas between the contour-lines, and 
the percentages to the total area of the loch, are as follows : 

to 25 feet 126 acres 68 per cent. 

25,, 50 35 19 

50,, 75 16 8 

Over 75 , 8 , 5 



185 100 

Temperature Observations. A surface reading at 10 a.m. on October 
22, 1902, when commencing the survey, gave 44 Fahr., but at 2 p.m. 
in the deepest part of the loch a series of temperatures gave identical 
readings, viz. 46'2, at the surface and at 10, 25, 50, and 75 feet. 

LochAilsh (see Plate LXIX.). Loch Ailsh lies about 10 miles to the 
west of Loch Shin, with the heights of Ben More Assynt and Coniveall 
rising to the north. It is a moderate-sized but rather shallow loch, 
containing trout and an occasional salmon or grilse. It is irregular in 
outline, slightly under a mile in length from north to south, with a 
maximum width in the northern portion exceeding half a mile. Its 
waters cover an area of about 245 acres, and it drains an area 44 
times greater an area of nearly 17 square miles. The maximum depth 
of 24 feet was observed in the north-eastern part of the loch, less than 
a quarter of a mile from the alluvial cone laid down at the mouth 
of the river Oykell on the northern shore. The volume of water is 
estimated at 88 million cubic feet, and the mean depth at 8J feet. The 
loch was surveyed on September 6, 1902, when the elevation of the 
lake-surface above the sea was found to be 498'5 feet, almost identical 
with that observed by the Ordnance Survey officers on August 29, 1871, 
viz. 498-4 feet. The highest drift-mark observed was 4 feet above the 
level of the water on the date of the survey. The southern and western 
portions of Loch Ailsh are covered by less than 10 feet of water, the 
deeper part lying along the eastern shore and towards the north-eastern 
angle of the loch. The area of the lake-floor covered by less than 10 
feet of water is about 173 acres, or 71 per cent, of the entire area, while 
that covered by more than 20 feet of water is only about 12 acres, or 
5 per cent. The temperature of the surface water at 2 p.m. on the 
date of the survey was 55 0> 3 Fahr., and a reading at a depth of 20 feet 
gave 54. 



302 BATHYMETRICAL SURVEY OF 

Loch Cr aggie (see Plate LXIX.). Loch Craggie is a small but rather 
deep loch, less than 3 miles to the south of Loch Ailsh, the road from 
Oykell Bridge to Lochinver running along the northern shore. It 
trends in a north-west and south-east direction, is nearly two-thirds of 
a mile in length, and covers an area of about 45 acres. The maximum 
depth of 40 feet was observed approximately in the centre of the loch. 
The volume of water is estimated at 30 million cubic feet, and the 
mean depth at 15J feet. It was surveyed on September 23, 1902, when 
the elevation of the lake-surface was found to be 505'95 feet above the 
sea; when visited by the Ordnance Survey officers on August 26, 1871, 
the elevation was 506'5 feet above sea-level. 

Loch Craggie is quite simple in conformation. The water is deep 
close to the shore all round, except towards the outflow at the south-east 
end, the area of the lake-floor covered by less than 10 feet of water 
being only about 15 acres, or 34 per cent, of the entire area ; more than 
half of the bottom is covered by water between 10 and 25 feet in 
depth, while about 6 acres, or 13 per cent., are covered by more than 
25 feet of water. Temperature observations taken at 3.30 p.m. on the 
date of the survey showed that the water was practically uniform in 
temperature from surface to bottom, the reading at the surface being 
52-8 Fahr., and at the depths of 15 and 30 feet, 52-5. 

Loch an Daimh (see Plate LXIX.). Loch an Daimh (or Damph) is 
situated about 7 miles to the south-west of Oykell Bridge, and about 
8 miles to the east of Ullapool on Loch Broom. Though at present in 
the eastern watershed, the day may not be far distant when it will be 
diverted to the west, for the small stream flowing into the Rhidorroch 
river is cutting back rapidly, is much lower than the loch, and will 
probably tap the loch at its south-west end. The shores rise well above 
the loch, and the south-eastern shore is wooded ; it is a good trout loch, 
but the fishing is preserved. Loch an Daimh is a narrow loch trending 
south-west and north-east, nearly 1| miles in length, with a maximum 
breadth of only one-fifth of a mile. Its waters cover an area of about 
173 acres, or a quarter of a square mile, and it drains an area of about 
2J square miles. The maximum depth of 52 feet was observed approxi- 
mately near the centre of the loch, but towards the south-west end. 
The volume of water is estimated at 205 million cubic feet, and the 
mean depth at over 27 feet. The loch was surveyed on August 23 and 
25, 1902, when the elevation of the lake-surface was found to be 
671 '5 feet above the sea identical with the elevation observed by the 
Ordnance Survey officers on August 1, 1870; during the winter of 
1901-2 the water rose 2 to 3 feet. 

Loch an Daimh is extremely simple in conformation, with no pro- 
nounced irregularities of the lake-floor. The 10-feet and 25-feet basins 
extend from end to end, and the 50-feet basin, half a mile in length, 



THE FRESH- WATER LOCHS OF SCOTLAND. 303 

occupies a central position. The offshore slope is in some places very 
steep, and the average slope outside the 25-feet contour is steeper 
than in the deeper water between 25 and 50 feet, as shown in the 
following table giving the areas between the contour-lines, and the 
percentages to the total area of the loch : 

to 25 feet 77 acres 44 '5 per cent. 

25 50 87 50-6 

Over 50 , 9 . 4 -9 



173 100-0 



The surface temperature on August 23, 1902, at 12.30 p.m., was 
57 Fahr.; and on August 25, at 11.45 a.m., 56. 

Loch Migdale (see Plate LXX.). Loch Migdale is situated close to 
the northern shore of the Dornoch firth, and less than a mile from Bonar 
Bridge at the head of that firth. It contains trout and pike, and the 
surrounding scenery is very fine, a conspicuous hill called Migdale Rock 
rising off the north-eastern shore. The island at the west end of the 
loch is artificial, composed of large and small stones ; a crossing passes 
from the western shore to the island, and was covered by a foot of water 
at the time of the survey. The loch trends in a north-west and south- 
east direction, and is nearly 2 miles in length, with a maximum width 
of nearly half a mile towards the north-west end, the loch narrowing 
gradually towards the opposite end. Its waters cover an area of 
about 260 acres, and it drains an area of about 7J square miles. The 
maximum depth of 49 feet was observed rather nearer the north-west 
than the south-east end. The volume of water is estimated at 242 
million cubic feet, and the mean depth at over 21 feet. Loch Migdale 
was surveyed on September 24, 1902, when the elevation of the lake- 
surface was found to be 113-6 feet above the sea; when visited by the 
Ordnance Survey officers on November 1, 1869, the elevation was 115'1 
feet above sea-level. 

The loch forms a simple basin, with a few minor undulations of 
the lake-floor. The contour-lines approach nearer to the eastern end, 
where the Spinningdale burn flows out, the water being shallower 
towards the opposite end, with weeds growing off the northern shore, 
at the entrances of Migdale burn and Munroe's burn. The area of the 
lake-floor covered by less than 10 feet of water is about 70 acres, or 
27 per cent, of the total area, while that covered by more than 25 feet 
of water is about 94 acres, or 36 per cent. Temperatures taken at 
6 p.m. on the date of the survey, in the deepest part of the loch, 
showed very little variation in the temperature of the water, the reading 
at the surface being 54-9 Fahr., at 25 feet 54'l, and at 40 feet 54. 



304 BATHYMETRICAL SURVEY OF 

Loch an Lagain (see Plate LXX.). Loch an Lagain (or Laggan) 
lies about 3J miles to the north-east of Bonar Bridge. It receives the 
outflow from Loch Laro (which was not sounded), and its superfluent 
waters are carried by the river Evelix, after a long winding course, 
into the Dornoch firth. It is a small, comparatively shallow loch, 
trending almost east and west, one mile in length, with a maximum 
width towards the western end of nearly a quarter of a mile, narrowing 
gradually towards the eastern end. Its waters cover an area of about 
68 acres, and it drains a relatively large tract of country, the area of 
which exceeds 8 square miles an area 74 times greater than that of 
the loch. The maximum depth of 18 feet was observed near the centre 
of the loch, but towards the northern shore. The volume of water 
is estimated at 23 million cubic feet, and the mean depth at 1\ feet. 
The loch was surveyed on September 25, 1902, but the elevation 
of the lake-surface above the sea could not be determined; the 
Ordnance Survey officers levelled the loch on November 23, 1869, and 
found the elevation to be 446'2 feet above sea-level. The lake-floor 
is quite simple in conformation, with no irregularities, the deeper water 
approaching nearer to the eastern than to the western end; the area 
covered by less than 10 feet of water is about 49 acres, or 71 per cent, 
of the total area of the loch. The temperature of the surface water was 
53-0 Fahr., and a reading at a depth of 9 feet gave 52-9. 

Loch Buidht (see Plate LXX.). Loch Buidhe (or Buie) lies amid 
moorland hills about 5 miles to the north-east of Bonar Bridge, the road 
from that place to Golspie running along its southern shore. It receives 
the outflow from Lochs Cracail Mor and Cracail Beag (which were not 
sounded), and flows, as already stated, into the head of Loch Fleet. It 
is a good trout loch, but an attempt to introduce salmon failed. The 
loch trends east and west, and is 1J miles in length, with a maximum 
breadth of nearly a quarter of a mile. Its waters cover an area of about 
133 acres, and it drains an area of about 8| square miles an area over 
40 times greater than that of the loch. The maximum depth of 36 feet 
was observed approximately in the centre of the loch. The volume 
of water is estimated at 68 million cubic feet, and the mean depth at 
11| feet. The loch was surveyed on September 25, 1902, when the 
elevation of the lake-surface above the sea was found to be 528-45 feet ; 
when visited by the officers of the Ordnance Survey on May 21, 1870, 
the elevation was 527-3 feet above sea-level. By means of the sluice 
at the east end of the loch the level of the water may be raised 4 or 
5 feet, but it is seldom, or never, used; according to the keeper, the 
water may fall 2 feet below the level on the date of the survey. 

Loch Buidhe is quite simple in conformation, the bottom sinking 
gradually on all sides from the shore to the deepest part, which occupies 
a central position. The area of the lake-floor covered by less than 10 



THE FRESH- WATER LOCHS OF SCOTLAND. 



02 

* 

JB -3 

3 I 

H ^ 



ll 

I ! 



Ratio to 
area of 






ill 

JH 



t 



-S5 



ill 



iillf 

52 a 5 



C >^ 7J Lt ;c 

C". 71 -* ^^ 



Lt ;c C -M t- X X 



>- x cc i- ^r re n "M i 



9 -^ ^ -* r -r ^ 



11 



1*1 



s- s 



II 



OOOC 00000 00 



--- r r ---- 



Lt ir: o t^ x 01 o * o o 

-- X -f ^ X t O X 
X i 







X-NI- o ip i^ ^ ^-? 

i :1 ^SSt-:22lS 

-M cc re x t 1^7 ^r ^ h 

k 



..lt. 



- 

-S'o > 



1 



age 



305 



\V 



306 BATHYMETRICAL SURVEY OF 

feet of water is about 66 acres, or 50 per cent, of the total area of the 
loch, while that covered by more than 25 feet of water is about 4 acres, 
or 3 per cent. Temperature observations taken in the deepest part of 
the loch at 1.30 p.m. on the date of the survey showed little variation, 
the reading at the surface being 52- 6 Fahr., at 20 feet 52-l, and at 
30 feet 52-0. 

The particulars regarding the lochs of the Shin basin are collected 
together in the table on p. 305 for convenience of reference and 
comparison. From this table it will be seen that in the eleven lochs 
under consideration, which cover an area of over 12 square miles, 
nearly 1600 soundings were taken, or an average of 129 soundings per 
square mile of surface. The aggregate volume of water contained in 
the lochs is estimated at 14,500 millions of cubic feet, and the area 
draining into them is nearly 240 square miles, or twenty times the 
area of the lochs. 



NOTES ON THE GEOLOGY or THE SHIN BASIN. 
By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. 

Of the area included in the basin of the Shin, only narrow belts 
along the west, north, and east margins have been mapped by the 
Geological Survey. The greater part of the tract is occupied by 
crystalline schists of the types so largely developed in the counties of 
Sutherland and Ross, to the east of the line of complication which 
stretches southwards from Loch Eriboll by the headwaters of the 
Cassley and the Oykell rivers to Ullapool. The course of the Moine 
thrust the most easterly of the great Post-Cambrian displacements 
described in the " Notes on the Geology of the Assynt District "* 
runs south from Gorm Loch Mor by Loch Ailsh to near Loch Craggie, 
thence it curves westwards to Knockan beyond the limits of the Shin 
basin. East of this dislocation, the metamorphic rocks include quartz 
schists, quartz-biotite granulites, garnetiferous muscovite-biotite schists 
and flaggy micaceous gneisses. These are pierced by igneous materials 
(granite and diorite) that cover considerable areas, as near Lairg. 

Along the eastern part of the basin there is a belt of Old Red 
Sandstone strata running in a north-east and south-west direction, its 
western limit being approximately denned by a line drawn from the 
Mound station to a point west of Edderton station. Both the middle 



See p. 178. 



THE FRESH- WATER LOCHS OF SCOTLAND. 307 

or Orcadian and the upper divisions of this formation are represented, 
the latter occurring between Tain and Tarbat Ness and northwards 
along the shore by Dornoch. 

Gorm Loch Mor. This lake, situated in the high plateau east of 
Ben More, lies in a rock basin formed mainly of Cambrian quartzite. 
Part of the floor, where the Garbh Allt enters the loch, may be composed 
of thrust Lewisian gneiss underlying these quartzites. The deepest 
sounding is 91 feet, and at the outlet the water flows over ledges of the 
higher or " pipe-rock " zone of the quartzite. Around the lake, the 
traces of glaciation are extremely abundant. Both the striae and the 
disposition of the carried boulders prove that, during the greatest 
extension of the later glaciers, the ice radiating from the east side of 
the Ben More range crossed the ridge in a north-east direction beyond 
Gorm Loch Mor and overflowed into Loch Shin. At a later stage, the 
glacier that issued from Coire a' Mhadaidh curved round Cailleach an 
t-Sniomha on the west side of Gorm Loch Mor, and moved north-west 
by Glen Beg to the head of Loch Glencoul. The quartzite plateau in 
the east part of the lake is dotted over with moraines, which there form 
the islands. 

Loch Aihh is a shallow lake the greatest depth being 24 feet 
partly enveloped in drift and solid rock. It rests on various zones of 
Cambrian age, including the quartzite, Fucoid beds, serpulite grit, 
and limestone with intrusive igneous materials, all overlying the Ben 
More thrust-plane. From the covering of drift, it is uncertain whether 
this lake is a true rock basin. Its surface level is 498'5 feet, and the 
rock first appears at the outlet at a height of 490 feet above Ordnance 
datum line. 

Loch Cr aggie is a true rock basin, the deepest sounding being 40 feet. 
The rocky barrier is formed by siliceous schists and mica-schists that 
are well exposed in the stream below the outlet and by the side of the 
road along the north bank of the lake. The height of the surface of 
the water above sea-level is 505-95 feet, and that of the solid rock where 
the bridge spans the Craggie burn below the outlet is 505 feet. The 
direction of the ice-movement during the later glaciation was parallel 
with the long axis of the lake. 

Lnch an, Daimh lies along a line of dislocation or fault that has been 
traced for a long distance in the crystalline schists south-westwards 
towards the head of Loch Broom. In the streams draining the hill 
slope on the northmost side the strata are exposed, which there consist 
of quartzose granulites with intercalations of mica-schist. On the 
higher part of the declivity the beds dip at gentle angles to the south- 
east, but on approaching the lake they are thrown into rapid folds 
parallel with its long axis, and are much crushed and shattered. At 
its lower end the lake is invaded by cones of alluvium brought down by 
the streams on either side. 



308 BATHYMETRICAL SURVEY OF 

NOTES ON THE BIOLOGY OF THE LOCHS OF THE SHIN BASIN. 
By JAMES MURRAY. 

Collections of plankton were made in eight lochs of the basin. The 
lochs are mainly characterised by the presence of two northern species 
of Diaptomus (D. laciniatus and D. laticeps), besides the common 
D. gracilis, and by the very numerous Desmids, many of which are of 
the western type. 

Each of the three species of Diaptomus was found in five lochs 
D. gracilis in Lochs Shin, a' Ghriama, Ailsh, Gorm Loch Mor, and 
Fiodhaig ; D. laciniatus in Lochs Shin, a' Ghriama, Merkland, Ailsh, and 
an Daimh ; D. laticeps (or a related species) in Lochs a' Ghriama, Ailsh, 
an Daimh, Gorm Loch Mor, and Fiodhaig. All three species occurred 
together only in two lochs (a* Ghriama and Ailsh), while in all the 
other lochs, except Merkland and an Lagain, there were two species; 
in Loch Merkland D. laciniatus was the only species seen. D. laticeps 
was identified in Lochs a' Ghriama and Ailsh; in Lochs an Daimh, 
Gorm Loch Mor, and Fiodhaig, a species of the same group occurred, 
but as only females or immature males were seen, it is not certain 
whether they were D. laticeps or the very closely related D. Wierzejskii. 

Among other Crustacea there is little to note Holopedium was 
only seen in Lochs Shin and a' Ghriama; Leptodora in Lochs Shin, 
a' Ghriama, and an Daimh ; Sida in Loch a' Ghriama only ; DiapJiano- 
soma in nearly all of the lochs. Nearly all the Daphnice of Loch 
Fiodhaig were males. 

Ilyocryptus acutifrons, G. O. Sars, was found in Loch Shin in 
August, 1903, being previously unrecorded for Great Britain. It was 
obtained in a shallow bay at the mouth of the Fiodhaig river. 

The Desmids of Loch Shin have been fully studied by Messrs. W. 
and G. S. West.* On the occasion of our visit the very great abundance, 
of individuals as well as species, was remarkable, exceeding anything 
that we had observed in other lochs. In Lochs a' Ghriama and Merk- 
land the species were also very numerous, and on the whole the same as 
in Loch Shin. In Lochs Ailsh, an Daimh, and an Lagain, few Desmids 
were seen, but all had some of the western species. In Gorm Loch 
Mor and Loch Fiodhaig no Desmids were noted. 

Pelagic Rotifera were abundant only in Lochs Shin, a' Ghriama, and 
Ailsh; in Loch Shin the plankton collections also included many 
littoral species, which must have been driven out by the stormy 
weather. Floscularia pelagica, Rousselet, was in Loch a' Ghriama 
only. Skeletons of the Heliozoan, Clatlwulina elegans, were abundant 
in Lochs Shin and a' Ghriama. 

* See Journ, Linn. Soc., Bot., vol. 35, p. 519, 1903. 



THE FRESH-WATER LOCHS OF SCOTLAND. 309 



LOCHS OF THE NAVER BASIN. 

THERE are five lochs within this basin to be dealt with here, of which 
the largest is Loch Naver, though Loch Coir' an Fhearna has a greater 
depth ; a few small lochs within the basin could not be sounded by the 
Lake Survey for lack of boats. The overflow from Loch na Meide is 
carried by the Amhainn Bheag and River of Mudale into Loch Naver, 
and shortly after leaving Loch Naver the river Naver is joined by the 
river Mallart, bearing the overflow from Lochs a' Bhealaich and Coir' 
an Fhearna, while still further on the river Naver is joined by the 
Langdale burn, bearing the overflow from Loch Syre. Of the total 
area of the basin (nearly 200 square miles), about 119 square miles, 
or 60 per cent., drain into these five lochs. 

Loch na Meide (see Plate LXXI.). Loch na Meide (or Meadie) lies 
about 10 miles to the south of Tongue, and about 22 miles to the north 
of Lairg, which is the nearest railway station. It trends nearly north 
and south, and is very irregular in outline, the northern portion being 
narrow, while the southern portion widens out considerably ; there is a 
very narrow and shallow constriction near the middle, which practically 
cuts the loch into two portions. It is 3J miles in length, and has a 
maximum breadth near the southern end of over a mile, the mean 
breadth of the entire loch being a quarter of a mile. Its waters cover 
an area of about 555 acres, or nearly 1 square mile, and it drains an 
area of 8 square miles. The maximum depth of 63 feet was observed in 
the wide southern portion of the loch, but towards the eastern shore, 
about 650 yards from the southern end, and only about 100 yards from 
one of the small unnamed islands. The volume of water is estimated at 
498 million cubic feet, and the mean depth at 20J feet. The loch was 
surveyed on September 25, 1902, when the elevation of the lake-surface 
was found, by levelling from bench-mark, to be 488*35 feet above the 
sea. 

Loch na Meide is very irregular in conformation, with many small 
islands in the southern half, the largest of which is named Eilean Mor. 
The deepest water was found near the southern end; a sounding in 
44 feet was taken about 200 yards from the southern shore, and there is 
a small area about one-third of a mile in length exceeding 50 feet in 



310 



BATHYMETRICAL SURVEY OF 



depth. In close proximity a sounding of 22 feet was taken, surrounded 
on all sides by deeper water. On approaching the central constriction, 
in which the depth is only 2 feet, the water shoals gradually though 
irregularly, and deepens again on proceeding towards the northern end, 




English Miles 
e 3 *. s 



FIG. 49. INDEX MAP OF THE NAVER, BOUGIE, KINLOCH, AND HOPE BASINS. 



where a maximum depth of 40 feet was observed about half a mile 
from the upper end, and where there is a small area about one-third of 
a mile in length exceeding 30 feet in depth. The following table 
gives the areas between the contour-lines, and the percentages to the 
total area of the loch, and shows that on the whole Loch na Meide is 



THE FRESH- WATER LOCHS OF SCOTLAND. 311 

rather shallow, since 70 per cent, of the lake-floor is covered by less 
than 25 feet of water: 

to 25 feet 388 acres 70 per cent. 

25,, 50 149 27 

Over 50 , 18 , 3 



555 100 

The temperature of the surface water at 10 a.m. on the date of the 
survey was 53 0- Fahr. The deposits brought up were all very dark 
(black) muds. 

Loch Naver (see Plate LXX1I.). Loch Naver lies about 5 miles to 
the south-east of Loch na Meide, with Ben Klibreck to the south rising 
gently up from the shore of the loch. Altnaharra Inn, at the west end 
of the loch, is a well-known rendezvous for anglers. On the northern 
shore Reidhachaisteil and Gruamamor,- and on the southern shore 
Ruighnasealbhaig, are the remains of considerable villages destroyed 
at the beginning of last century when the crofters were turned out. 
There are the ruins of Pictish towers near Gruamamor and on the 
island close to the opposite (southern) shore, and the remains of several 
artificial crannogs rise towards the surface of the water, in one case 
reaching above the surface. Loch Naver is broadly sinuous in outline, 
the general trend being east-north-east and west-south-west, while the 
upper portion for about a mile runs east and west, and it exceeds 6 
miles in length. It is a comparatively narrow loch, the maximum 
width towards the west end not exceeding two-thirds of a mile, whence 
the width gradually diminishes towards the east end, the mean breadth 
of the entire loch being about one-third of a mile, or 6 per cent, of the 
length. Its waters cover an area of about 1446 acres, or 2J- square 
miles, and it drains directly an area of nearly 81 square miles; but 
since it receives the outflow from Loch na Meide, its total drainage 
area is nearly 89 square miles. The maximum depth of 108 feet was 
observed in the wider part of the loch about a mile from the west end. 
The volume of water contained in the loch is estimated at 2461 millions 
of cubic feet, and the mean depth at 39 feet. The loch was surveyed 
on September 24 and 25, 1902, when the elevation of the lake-surface 
was determined, by levelling from bench-marks, as being 247 '6 feet 
above the sea ; when visited by the officers of the Ordnance Survey on 
June 24, 1870, the elevation was found to be 246'9 feet above sea-level. 
The highest drift-mark observed was 4J feet above the surface of the 
water at the time of the survey, and it was said that the water might 
fall to the extent of 4 feet, giving a range in level of about 8J feet. 

The floor of Loch Naver is rather irregular, as may be seen in the 
longitudinal section taken along the axis of maximum depth, which 



312 BATHYMETRICAL SURVEY OF 

shows how the bottom rises and falls on proceeding from one end of 
the loch to the other. The 25-feet contour-line is discontinuous opposite 
the entrance of the Allt Gruama Beag, where the deepest sounding was 
24 feet, the water deepening both to the east and to the west. The 
50-feet contour is continuous, enclosing an area nearly 4 miles in length, 
distant from the east end about 1| miles, and approaching to within 
one-third of a mile from the west end ; within this area, however, the 
bottom rises in two places, where soundings of 40 and 43 feet were 
taken. There is a small isolated 75-feet area opposite Carn Gruama 
Beag, based on soundings of 76 and 80 feet, separated from the principal 
75-feet basin by an interval of over a quarter of a mile, in which the 
greatest depth is 62 feet; the main 75-feet area is 2J miles in length, 
and approaches to within three-quarters of a mile from the west end. 
There are two very small 100-feet areas, based upon isolated soundings 
of 100 and 108 feet, the former opposite Gruamamor, the latter farther 
up the loch west of Reidhachaisteil. A short distance to the west of 
the deepest sounding (108 feet) is a rise of the bottom covered by 40 
feet of water already mentioned, and to the north-east near the northern 
shore is a bank covered by only 1 foot of water surrounded by much 
deeper water. Off the southern shore at Coill Ach' a' Chuil, towards 
the east end of the loch, is another bank with 6 feet of water on it, 
in close proximity to a sounding of 30 feet. The following table gives 
the areas between the consecutive contour-lines and the percentages 
to the total area of the loch : 

to 25 feet 551 acres 38 '1 per cent. 

25,, 50 425 29-4 

50,, 75 301 20-8 

75,, 100 ,, 167 11-6 

Over 100 , 2 . O'l 



1446 . 100-0 



Temperature observations taken on September 24, 1902, gave 
readings of 54 Fahr. at the surface, at 25 feet, and at 50 feet; while 
at 80 feet the temperature was 53'5. 

Loch a' Bhealaich (see Plate LXXIII.). Loch a' Bhealaich (or 
a-Vellich, or Vealloch) lies about 4J miles to the south of the western 
portion of Loch Naver, with Ben Klibreck rising between them. It is 
almost continuous with the larger Loch Coir' an Fhearna, the connect- 
ing stream between them being only about 200 yards in length, and the 
difference in level less than 2 feet. To the north of the two lochs 
Ben Klibreck slopes gently up to over 3000 feet, while the ground to 
the south is not so high, but much steeper ; so steep is that around 
Loch a' Bhealaich (which lies in a very fine corrie) that even at noon 



THE FRESH-WATER LOCHS OF SCOTLAND. 313 

on the date of the survey the sun could not be seen, except by going 
over to the north-west shore. The two lochs trend in a north-east and 
south-west direction, and together have a total length of 4f miles. 
Loch a' Bhealaich exceeds 1| miles in length, with a maximum breadth 
of a quarter of a mile. Its waters cover an area of about 175 acres, 
or over a quarter of a square mile, and it drains an area of nearly 6 
square miles. The maximum depth of 80 feet was observed towards 
the north-east end of the loch. The volume of water is estimated at 
238 million cubic feet, and the mean depth at over 31 feet. The loch 
was surveyed on October 17, 1902, when the elevation of the lake- 
surface was found to be 572-2 feet above sea-level. The water might 
rise 2 or 3 feet above, and fall about 1J feet below, that level. 

The main body of Loch a' Bhealaich is quite simple in conformation, 
but at the north-east end there is a small expansion of the loch, having 
a maximum depth of 14 feet, separated from the main body by a 
constriction in which the depth is 9 feet. The 25-feet area is over a 
mile, and the 50-feet area over half a mile, in length, the deeper water 
being contained in the north-eastern half of the loch, the deepest 
sounding in 80 feet having been taken about a quarter of a mile from 
the north-eastern shore. The areas between the contour-lines and the 
percenta ges to the total area of the loch are as follows : 

to 25 feet 77 jlpfes 44 per cent. 

25 50 69*7, 39 

Over 50 29 17 

175 , 100 



Temperature observations taken in the deepest part of the loch 
gave 48-9 Fahr. at the surface and at 40 feet, a reading at 76 feet 
giving 48'4. 

Loch Coir' an Fhedrna (see Plate LXXIII.). Loch Coir' an Fhearna 
(or Corr, or a-Choire) is a fine sheet of water, well wooded along the 
south-eastern shore, the Duke of Sutherland's lodge standing at the 
lower (north-eastern) end. It is over 3 miles in length, and compara- 
tively uniform in breadth, the maximum breadth being half a mile, 
and the mean breadth over one-third of a mile. Its waters cover an 
area of about 737 acres (considerably over 1 square mile), and it drains 
directly an area of about 18J square miles, but since it receives the 
outflow from Loch a' Bhealaich, its total drainage area is about 24J 
square miles. The maximum depth of 151 feet was observed com- 
paratively near the south-west end. The volume of water is estimated 
at 1886 millions of cubic feet, and the mean depth at nearly 59 feet. 
The loch was surveyed on October 15 to 17, 1902; the elevation of 
the lake-surface on commencing the survey on the 15th was found to 



314 BATHYMETRICAL SURVEY OP 

be 569*7 feet above sea-level, but the water rose to the extent of 
9 inches by the 17th, when Loch a' Bhealaich was surveyed. On the 
15th the water was about its lowest level, and might rise 2 or 3 feet. 
Loch Coir an Fhearna is quite simple in conformation, with the 
deeper water lying towards the south-west end that is, towards the 
peninsula separating it from Loch a' Bhealaich, and the fact that in 
Loch a' Bhealaich the deeper water also approaches the separating 
peninsula seems to suggest that the two lochs may at one time have 
been continuous. The contour-lines all enclose continuous areas, 
approaching much nearer to the south-west than to the north-east 
end, indicating a more gentle slope towards the north-east. Thus 
the 100-feet area is distant about three-quarters of a mile from the 
north-east end, but approaching to within less than a quarter of a 
mile from the south-west end, and the maximum depth of 151 feet 
was observed about half a mile from the south-west end. The slope 
along the south-east shore is as a rule steeper than along the opposite 
shore, and this is especially the case off Creag Chraobhach, at the 
position of the deepest sounding, where a sounding in 46 feet was 
taken about 50 feet from the shore. This is shown in cross-section G-H 
on the map. The areas between the contour-lines at intervals of 
50 feet, and the percentages to the total area of the loch, are as 
follows : 

to 50 feet 343 acres 46 '6 per cent. 

50,, 100 269 36-5 

100,, 150 124 16-8 

Over 150 , 1 O'l 



737 ,, 100-0 



Temperature observations taken in the deepest part of the loch at 
1.30 p.m. on October 16, 1902, gave readings of 50-0 Fahr. at the 
surface, at 20 feet, and at 80 feet, and a reading of 49-8 at 130 feet. 

Loch Syr e (see Plate LXXIV.). Loch Syre lies about 3 miles to 
the north of the east end of Loch Naver, on the high ground between 
Strath Naver and Loch Laoghal, the last-named loch being only about 
1 miles distant to the west. It is an irregular shallow loch, with 
several islands in it, and the eastern part is full of stones. From east 
to west it has a length of nearly three -quarters of a mile, with a 
maximum breadth of over half a mile. Its waters cover an area of about 
106 acres, and it drains an area of over 5 square miles. The maximum 
depth of 12 feet was observed in the south-eastern part of the loch. 
The volume of water is estimated at 25 million cubic feet, and the 
mean depth at 5J feet. The loch was surveyed on October 1, 1902, 
when the elevation of the lake-surface was found to be 412-8 feet above 
the sea; when levelled by the officers of the Ordnance Survey on 



THE FRESH-WATER LOCHS OF SCOTLAND. 315 

July 23, 1870, the elevation was 411-4 feet above sea-level. The level 
of the loch has been raised over a foot by means of a dam above the 
first island, and it was proposed to raise it still further to the extent of 
2 or 3 feet. At the time of the survey the highest drift-mark observed 
was about 2 feet above the water, which might fall about a foot. 

The floor of Loch Syre is irregular, as might be expected from its 
extremely irregular outline and many islands. The deepest water was 
found in the south-eastern angle of the loch, where there is a small 
area over 10 feet in depth, the deepest cast in 12 feet having been 
taken about 100 yards from the eastern shore and 150 yards from the 
southern shore. Between the deepest sounding and the southern shore 
the bottom rises to 9 feet and sinks again to 11 feet close inshore. 
The area of the lake-floor covered by less than 10 feet of water is about 
97 acres, or 92 per cent, of the entire area of the loch. The temperature 
of the surface water on the date of the survey was 54 0< 7 Fahr. 



316 BATHYMETRICAL SURVEY OF 



LOCHS OF THE BOUGIE BASIN. 

THE three lochs to be dealt with here form a connected series, the 
overflow from Loch Cuil na Sithe being carried into Loch Laoghal by 
the Lbn Achadh na h-Aibhne, while Lochs Laoghal and Creagach are 
almost continuous, the connecting stream being only about 200 yards 
in length. Of the total area of the basin (about 62 square miles), about 
35 square miles, or 56 per cent., drain into these three lochs. 

Loch Cbil na Sithe (see Plate LXXIV.). Loch Cuil na Sithe (or 
Coulside) is a small narrow loch lying over a mile to the west of the head 
of Loch Laoghal, and about 5 miles to the north of Altnaharra, at the 
head of Loch Naver. It trends east-north-east and west-south-west, 
and is very nearly a mile in length, varying little in width, the 
maximum breadth being about 250 yards. Its waters cover an area 
of about 58 acres, and it receives the drainage from a comparatively 
large tract of country, the drainage area being about 9 square miles 
an area a hundred times greater than that of the loch. The maximum 
depth of 14 feet was observed in two places near the middle of the 
loch. The volume of water is estimated at 19 million cubic feet, and 
the mean depth at 7J feet. The loch was surveyed on September 29, 
1902, but the elevation of the lake-surface above the sea could not be 
determined; a drift-mark was observed over 6 feet above the water, 
which might fall to the extent of a foot, giving a range in level 
exceeding 7 feet. 

Loch Cuil na Sithe is extremely simple in conformation, and com- 
paratively uniform in depth. The upper portion is being silted up, 
and is occupied by weeds, and the lower portion is full of stones. The 
10-feet contour coincides approximately with the outline of the loch, 
and encloses an area of about 20 acres, or 35 per cent, of the total 
area of the loch. The temperature of the surface water on the date of 
the survey was 56-2 Fahr., and a reading at a depth of 11 feet gave 
53-9. 

Loch Laoghal (see Plate LXXV.). Loch Laoghal (or Loyal) is 
distant about 4| miles from Tongue and about 6 miles from Altnaharra, 
the road between these two places running alongside the western shore 
of the loch throughout its whole length. To the west rises Ben Loyal, 



THE FRESH- WATER LOCHS OF SCOTLAND. 317 

one of the most beautiful of mountains, with picturesque outline, the 
highest point exceeding 2500 feet; beyond Leitirmhor the granite is 
being quarried for building purposes, leaving a great scar on the 
hillside. To the east of the northern portion of the loch rises Beinn's 
Tomaine (Ben Stomino) to a height of 1728 feet, along the base of 
which the shore of the loch is thickly wooded. In outline the loch 
resembles somewhat a Wellington boot, with the toe pointing in a 
westerly direction, while the body of the loch trends almost north 
and south. The loch is 4 miles in length, with a maximum breadth 
of nearly a mile, the mean breadth exceeding half a mile. The waters 
of the loch cover an area of about 1630 acres, or over 2| square miles, 
and it drains directly an area of over 24 square miles, but since it 
receives the overflow from Loch Cuil na Sithe, its total drainage area 
exceeds 33 square miles. The maximum depth of 217 feet was 
observed near the foot of the loch, little more than half a mile from 
the northern shore. The volume of water contained in the loch is 
estimated at 4628 millions of cubic feet, and the mean depth at 65J 
feet. The loch was surveyed on September 26 to 29, 1902, and the 
elevation of the lake-surface 011 commencing the survey was found, 
by levelling from bench-mark, to be 369-9 feet above the sea; when 
levelled by the officers of the Ordnance Survey on August 29, 1870, 
the elevation was found to be 369'2 feet above sea-level. The highest 
drift-mark observed was 2J feet above the surface of the water at the 
time of the survey, and it was stated that the water might fall to 
the extent of a foot. 

Loch Laoghal contains two deep basins, the larger and deeper in 
the northern portion of the loch, and the smaller and shallower 
towards the head of the loch, separated by a shoaling of the bottom 
about 2^ miles from the foot of the loch, where there is a slight 
constriction in the outline. The 50-feet con tour-line is continuous, and 
encloses an area about 4 miles in length, extending from quite close 
to the northern end to within half a mile from the south-western end. 
There are two 100-feet basins : the smaller one approaches to within 
less than a mile from the head of the loch, and is three-quarters of a 
mile in length, the maximum depth observed therein being 137 feet, 
about 1J miles from the south-west end; the larger one is over 2 miles 
in length, and approaches to within about 250 yards from the northern 
end, enclosing the deepest part of the loch. The 1 50-feet area is about 
1J miles in length, and distant about a quarter of a mile from the 
northern end. The 200-feet area is nearly three-quarters of a mile in 
length, distant less than half a mile from the northern end. The 
longitudinal section on the map shows how rapidly the water deepens 
on proceeding from the northern end along the central line of the loch, 
while the opposite end of the loch is comparatively shallow and the 
slope of the bottom there gentle; it also shows the considerable rise 



318 



BATHYMETRICAL SURVRY OP 



of the bottom between the two deep basins. The cross-section G-H 
is taken at the position of the deepest sounding, and shows a slight 
rise of the bottom off the western shore from 80 to 75 feet. This 
section shows a steep offshore slope at both sides of the loch, but more 
especially off the eastern shore, where a sounding in 78 feet was taken 
about 80 feet from shore, and this steep slope off the eastern shore 
is continued to the northward, where a sounding in 48 feet was taken 
about 60 feet from shore. The soundings taken on the rise between the 
two deep basins indicate a rather uneven floor; for instance, one line 
of soundings from west to east shows that the bottom sinks gradually 
from the western shore to 86 feet, then rises to 60 feet, sinks to 
75 feet, rises to 30 feet, sinks slightly again to 32 feet, and then rises 
towards the eastern shore ; a little farther south a sounding was taken 
in 40 feet between two deeper soundings (54 and 57 feet). 

The following table gives the approximate areas between the 
consecutive contour-lines, and the percentages to the total area of 
the loch : 



Oto 50 feet 
50,, 100 
100,, 150 ,, 
150,, 200 ,, 
Over 200 , 



612 acres 
522 
246 
200 
49 

1629 , 



38 per cent. 
32 
15 
12 
3 

100 



Temperature Observations. Many observations of the temperature 
of the surface water in Loch Laoghal were taken on September 26, 27, 
and 29, 1902, and two serial temperatures were taken on September 29, 
one in each of the two deep basins. The surface temperature varied 
from 52-5 to 53'6 Fahr. The serials gave the following results : 



Depth in feet. 


Deepest part of Jocli. 
Sept. 29, 1902, 
noon. 


Southern deep basin. 
Sept. 29, 1902, 
2 p.m. 




Fahr. 


Fahr. 





53-0 


53-6 


10 


52-5 


53-4 


15 


52-4 




20 


52-5 




25 


52-5 


52 : 9 


27-5 




52-6 


30 




53-6 


35 


... 


52-2 


40 




524 


50 


52 : 5 


52-4 


70 


524 


52-3 


100 


52-4 


52-5 


125 


50-9 


135 


47-8 


52-3 


145 


46-7 


... 


150 


46-5 




195 


46-1 


... 



THE FRESH-WATER LOCHS OF SCOTLAND. 319 

These observations show an extreme range throughout the loch 
amounting to 7'5, but the greater part of this range was observed 
beyond the depth of 100 feet in the deepest part of the loch, the range 
from the surface down to 100 feet not exceeding l-4. In the southern 
shallower basin the temperature varied little down to the bottom in 
135 feet, there being no decrease in temperature beyond 100 feet, 
whereas at a depth of 135 feet in the northern deeper basin the tem- 
perature was 4 0> 5 lower than at a similar depth in the southern basin, 
and the temperature at the bottom of the deeper basin was 6 lower 
than anything observed in the shallower basin. 

Loch Creagach (see Plate LXXV.). Loch Creagach (or Craggie) lies 
immediately to the north of Loch Laoghal and at the same level, the 
short stream between them having a slight current flowing from Loch 
Laoghal into Loch Creagach. At the north end of Loch Creagach there 
is a small expansion of the outflowing river, called Loch Slaim (or 
Slam), which was not sounded. The general trend of Loch Creagach is 
nearly north and south, with a slight bend in the outline, the northern 
portion running towards the north-east. It is over 1J miles in length, 
with a maximum width in the southern portion of half a mile. Its 
waters cover an area of nearly 300 acres, or nearly half a square mile, 
and it drains directly an area of 1| square miles; but since it receives 
the outflow from Lochs Laoghal and Ciiil na Sithe, its total drainage 
area is nearly 35 square miles. The maximum depth of 84 feet was 
observed near the middle of the loch. The volume of water is estimated 
at 429 million cubic feet, and the mean depth at 33 feet. The loch 
was surveyed 011 September 27, 1902, when the elevation of the lake- 
surface was found to be identical with that of Loch Laoghal, viz. 369'9 
feet above the sea; when levelled by the Ordnance Survey officers on 
August 27, 1870, the elevation was 369-2 feet above sea-level, as in 
the case of Loch Laoghal. 

Loch Creagach resembles Loch Laoghal in that it contains two deep 
basins, which are separated by shallower water at the position of the 
constriction in the outline of the loch towards the northern end. The 
deeper basin occupies the wide southern portion of the loch, towards 
the peninsula separating this loch from Loch Laoghal, in which also 
the deeper water approaches the dividing peninsula, suggesting that 
at one time the two lochs may have formed a continuous sheet of water. 
The principal 50-feet area is about three-quarters of a mile in length, 
distant less than a quarter of a mile from the southern end of the loch. 
Within this basin there is a small elevation covered by 47 feet of water 
in the widest part of the loch towards the eastern shore. The maximum 
depth of the loch (84 feet) occurs a short distance to the north of this 
elevation, and about three-quarters of a mile from both ends, but 
towards the western shore, as will be seen in cross-section C-D on the 



320 BATHYMETRICAL SURVEY OF 

map. Towards the northern end of the loch lies the second 50-feet area, 
based on soundings of 50 and 51 feet, and of small extent, the greatest 
depth recorded on the ridge separating the two deep basins being 
20 feet close to the eastern shore. The contour of the bottom is shown 
in the longitudinal section A-B on the map. The areas between the 
consecutive contour-lines, and the percentages to the total area of the 
loch, are as follows: 

to 25 feet 138 acres 

25,, 50 78 

50,, 75 74 
Over 75 7 




297 100-0 



The temperature of the surface water on the date of the survey was 
54 Fahr., and four readings beneath the surface in the deepest part of 
the loch gave identical results, viz. 53 at depths of 10, 25, 50, and 
70 feet. 






THE FRESH- WATER LOCHS OF SCOTLAND. 321 



LOCHS OF THE KINLOCH BASIN. 

THERE are two lochs to be dealt with here, viz. Loch Chaluim and 
Loch an Dithreibh, the superfluent waters of which are carried into 
the Kyle of Tongue by the Amhainn Ceann Locha (or Kinloch river). 
Loch Chaluim is the only one of several small lochs in the basin which 
could be sounded, and it flows by the Allt an Dithreibh into Loch an 
Dithreibh. The two lochs form a complete contrast in outline and 
conformation of the bottom. 

Loch Chaluim (see Plate LXXVI.). Loch Chaluim lies on the 
south-western flank of Beiun Laoghal, little more than a mile from Loch 
Cuil na Sithe in the Borgie basin. It is most irregular in outline and 
in conformation, with one comparatively large island, and with weeds 
obstructing many of the bays. Measured in a south-west and north- 
east direction, it is about three-quarters of a mile in length, with a 
maximum breadth of half a mile, its waters covering an area of about 
96 acres. The maximum depth of 30 feet was observed in the extreme 
western portion of the loch, the mean depth being estimated at 8 feet, 
and the volume of water at 33 million cubic feet. The loch was 
surveyed on September 29, 1902, but the elevation of the lake-surface 
above the sea could not be determined. 

Loch Chaluim is on the whole shallow, only three soundings exceed- 
ing 20 feet having been recorded in the most westerly expansion of the 
loch. There are two 10-feet basins, the principal one extending from 
the extreme west end of the loch to beyond the island, filling up the 
south-western expansion of the loch to the south of the island, and 
enclosing the deepest part of the loch, the smaller one lying in the 
eastern and south-eastern expansions of the loch, and having a maximum 
depth of 17 feet. The greater part of the lake-floor is covered by less 
than 10 feet of water, equal to about 69 acres, or 72 per cent, of the 
total area. 

Temperature Observations. A series of temperatures was taken in 
the deepest part of the loch, with the following results : 



322 BATHYMETRICAL SURVEY OF 

Surface . 55'8 Fahr. 

2 feet 55-7 

3 55*4 

3-5,, 55'2 

4 53-6 

5 53'4 

10 53-0 ,, 

20 53'l ,, 

This series shows a range of 2 0> 8, there being a fall of no less than 
l-6 between 3J and 4 feet. 

Loch an Dithreibh (see Plate LXXVL). Loch an Dithreibh (or 
Deerie, or Derry) lies less than 3 miles to the south of the head of the 
Kyle of Tongue, with Ben Loyal to the east and the lofty Ben Hope, a 
magnificent object in the landscape, to the west. The general trend 
of the loch is north-north-east and south-south-west, the main body 
of the loch trending almost north and south, and throwing out an arm 
towards the north-east. The loch is over l miles in length, the main 
body being approximately uniform in width, with a maximum breadth 
of two-thirds of a mile, while the north-eastern arm is much narrower ; 
the mean breadth of the entire loch is nearly half a mile. Its waters 
cover an area of about 475 acres, or three-quarters of a square mile, 
and it drains directly an area of 10 square miles; but since it receives 
the overflow from Loch Chaluim, its total drainage area is 12f square 
miles. The maximum depth of 157 feet was observed approximately 
near the centre of the main body of the loch. The volume of water 
is estimated at 1366 million cubic feet, and the mean depth at 66 feet. 
The loch was surveyed on October 1, 1902, when the elevation of the 
lake-surface was found, by levelling from bench-mark, to be 267*45 
feet above the sea ; when levelled by the officers of the Ordnance Survey 
on October 26, 1870, the elevation was 267*8 feet above sea-level. 

Loch an Dithreibh includes two basins (1) a larger deep basin in 
the main body of the loch, and (2) a smaller shallower basin in the 
north-eastern arm, separated by a rise of the bottom on which the 
deepest sounding was 49" feet. The maximum depth observed in 
the small subsidiary basin was 59 feet, and the separating ridge is 
irregular, for a sounding in 21 feet was taken in its central part 
surrounded by deeper water. The 25-feet contour-line is continuous 
from end to end of the loch, coinciding approximately with the outline 
of the loch, but approaching close to the eastern shore off Creag an 
Dithreibh and Creag na Luath-ghaire. The 50-feet area is cut into 
two portions, as already indicated, the main portion approaching close 
to the southern end of the loch and exceeding 1 mile in length. The 
75-feet area is nearly a mile in length, and at its northern border the 
lake-floor shows conspicuous undulations, giving to the 75-feet contour- 



THE FRESH- WATER LOCHS OF SCOTLAND. 323 

line a strikingly sinuous character. The 100-feet area has a length 
of three-quarters of a mile, approaching comparatively very close to 
the southern shore, where a sounding in 115 feet was recorded about 
150 yards off shore. The 125-feet area exceeds half a mile in length, 
and the small 150-feet area, based upon soundings of 151, 152, and 157 
feet, occupies an approximately central position. Along the eastern 
shore the slope of the bottom is in places very steep. Off Creag na 
Luath-ghaire a sounding of 40 feet was taken about 80 feet off shore, 
and another so'unding in 49 feet about 70 feet off shore, while off Creag 
an Dithreibh one sounding was taken in 65 feet about 100 feet off shore, 
and another sounding in 65 feet about 60 feet off shore. This last- 
mentioned sounding gives an angle of slope exceeding 45, the fall 
exceeding 1 foot per foot. The areas between the consecutive contour- 
lines at equal intervals, and the percentages to the total area of the 
loch, are as follows: 

to 50 feet 204 acres 42*9 per cent. 

50,, 100 150 31-4 

100,, 150 113 23-9 

Over 150 . 9 , 1'8 



476 ,, 100-0 



Temperature Observations, A series of temperatures taken in the 
deepest part of the loch on the date of the survey gave the following 
results : 

Surface 54'0 Fahr. 

25 feet 53'5 

50 53-0 

100 52-5 

125 - ... 48-6 

145 48-4 

This series shows a range of 5'6 from surface to bottom, the greatest 
fall of temperature occurring beyond the depth of 100 feet a fall 
equal to about 4 between 100 and 125 feet. 



324 BATHYMETRICAL SURVEY OF 



LOCHS OF THE HOPE BASIN. 

THE only loch to be dealt with here is the large Loch Hope, one 
of the most important and the most northerly of the Sutherlandshire 
lochs. There are several small hill lochs within the basin, which 
could not be sounded at the time of the visit of the Lake Survey. 
The headwaters of the basin take their rise on the flanks of Ben Hee, 
of Meallan Liath, and of Meall Horn, whose summits attain heights 
exceeding 2500 feet. The total area of the basin is 75 square miles, 
of which nearly the whole drains into Loch Hope. 

Loch Hope (see Plate LXXVII.). Loch Hope lies close to the eastern 
shore of Loch Eriboll on the north coast of Scotland, at an elevation 
of only 12 \ feet above sea-level, so that a slight subsidence would 
convert it into an arm of the sea and a branch of Loch Eriboll. The 
natives declare that the sea never enters the loch, though ordinary 
spring tides attain a point not more than half a mile from the foot 
of the loch, and at the upper end three terraces are to be seen, and 
traces perhaps of a fourth. Ben Hope rises very steeply to a height 
of over 3000 feet to the south-east of the head of the loch, and the 
ground further north and to the west, though not so high, is also 
steep close to the shore; some parts of the shores are well wooded. 
The loch is free from islands, but on the date of the survey a reputed 
old castle was just showing a few inches above the water about a mile 
from the foot of the loch. The trend of the loch is almost north and 
south, and the total length exceeds 6 miles. The two ends of the loch 
are narrow, but it broadens out in the central portion, where there is 
a maximum breadth of three-quarters of a mile; the mean breadth 
of the entire loch is over one-third of a mile. The waters of the loch 
cover an area exceeding 1500 acres, or 2J square miles, and it drains 
an area exceeding 73 square miles. The maximum depth of 187 feet 
was observed about midway between the two ends of the loch. The 
volume of water is estimated at 4032 millions of cubic feet, and the 
mean depth at 61^ feet. The loch was surveyed on September 30, 1902, 
when the elevation of the lake-surface was found, by levelling from 
bench-mark, to be 12-55 feet above the sea; when levelled by the 
officers of the Ordnance Survey on August 9, 1858, the elevation was 



THE FRESH- WATER LOCHS OF SCOTLAND. 325 

12'3 feet above sea-level. The highest drift-mark observed was 9 feet 
above the surface of the water on the date of the survey, and, according 
to the local ghillie, the water might fall 2 feet lower, giving a total 
range in level of about 11 feet. 

The floor of Loch Hope is somewhat uneven. Proceeding from the 
lower (northern) end of the loch for a quarter of a mile, one meets with 
a small 25-feet area, based on soundings of 26, 30, and 32 feet, whence 
the bottom rises in the vicinity of the reputed old castle already 
mentioned, which lies toward the eastern shore ; off the opposite shore 
in this locality there were many boulders in the water. Thence pro- 
ceeding to the southwards, the water rapidly deepens until it attains 
a depth of 104 feet opposite the entrance of the Allt an Ruighein, 
about 1J miles from the foot of the loch. Thence for a distance of 
about three-quarters of a mile the bottom rises again until the depth 
in the centre is 44 feet, with deeper water on both sides. This shoal 
coincides with a narrowing in the outline of the loch, whence to the 
south the loch broadens out and the water deepens so rapidly that at 
a distance of little more than half a mile from the 44-feet sounding the 
maximum depth of the loch (187 feet) is met with. A section across 
the loch in the position of the deepest sounding is shown in cross- 
section C-D on the map. From this position the bottom rises gradually, 
though irregularly, towards the head of the loch. A section down the 
centre of the loch along the axis of maximum depth is shown in 
longitudinal section A-B on the map, which brings out the salient 
features in the conformation of the lake-floor, but gives no indication 
of some of the minor irregularities. For instance, the 44-feet shoal 
already referred to is not shown because a depth of 56 feet occurs 
nearer the western shore, nor another shoaling covered by 117 feet of 
water to the south of the deepest sounding. The offshore slope is in 
some places rather steep for instance, along the eastern shore, where 
off the entrance of the Allt a' Mhuilinn a sounding in 53 feet was taken 
about 60 feet from shore, and off the entrance of the Allt a' Phris Ghil 
a sounding in 28 feet was taken about 30 feet from shore ; also along 
the western shore about 1J miles from the head of the loch, where a 
sounding in 25 feet was taken about 30 feet from shore. The following 
table gives the approximate areas between the contour-lines at equal 
intervals, and the percentages to the total area of the loch : 

Oto 50 feet 723 acres 

50,, 100 .474 
100,, 150 218 

Over 150 , 91 




1506 , 100-0 



Temperature Observations. A series of temperatures was taken at 



326 



BATHYMETRICAL SURVEY OF 



PQ 



Ill 

III 



III 

Ml 






& a 



loll 



above 
Fee 



CO CO ^H 









Cft O5 












s 



8*3 



11 
II 



"o-S 

STJ 
is 



II 

S bo 

SI 



Jo 



If 

*J 

3-s 

!l 

*% 



THE FRESH- WATER LOCHS OF SCOTLAND. 327 

3 p.m. on the date of the survey in the deepest part of the loch, with 
the following results : 

Surface 54'6 Fahr. 

5 feet 54-6 

10 . 54-5 

25 ,, 54-2 

50 ,, 54-0 

100 53-3 

120 53'0 

135 52-l 

150 ,, 49-2 

This series shows a range from surface to bottom amounting to 
5*4. The upper layers of water are practically uniform in temperature, 
the decrease from the surface down to 50 feet being only 0> 6, down to 
100 feet l-3, and down to 120 feet l-6, whereas between the depths 
of 120 and 150 feet the fall of temperature was 3-8. It was stated 
that the loch freezes all over in winter. 

The details regarding the lochs in the Naver, Borgie, Kinloch, and 
Hope basins are collected together in the table on p. 326 for convenience 
of reference and comparison. From this table it will be seen that in the 
eleven lochs under consideration over 1400 soundings were taken, and 
that the aggregate area of the water surface is over 11 square miles, so 
that the average number of soundings per square mile of surface is 127. 
The aggregate volume of water contained in the lochs is estimated at 
about 15,600 millions of cubic feet. The area drained by these lochs 
is about 239J square miles, or twenty-two times the area of the lochs. 



NOTES ON THE GEOLOGY OF THE DISTRICT BETWEEN LOCH HOPE AND 

STRATH NAVER. 

By B. N. PEACH, LL.D., F.R.S., and J. HORNE, LL.D., F.R.S. 

The district extending from Loch Hope to Strath Naver, in the 
north of Sutherland, has not yet been wholly mapped by the Geological 
Survey. 

The north-western tract, embracing the lower part of Loch Hope, 
comes within the belt of territory affected by the Post-Cambrian move- 
ments to which reference has been made in the description of the geology 
of the districts of Loch Assynt and Loch Maree.* Hence, on the hill- 
slopes on either side of the river Hope, we find various subdivisions of 

See pp. 178 and 233. 



328 BATHYMETRICAL SURVEY OF 

the Cambrian system, repeated by folds and reversed faults, and overlaid 
by slices of Archaean gneiss, which resemble portions of the old floor on 
which the Cambrian strata rest unconformably west of Loch Eriboll and 
the Kyle of Durness. 

East of these displaced masses there is a great succession of crystalline 
schists stretching eastwards to Strath Naver, which, in the north of 
Sutherland, are everywhere separated from the rocks to the west by a 
powerful line of disruption, termed the Moine thrust. They consist 
of two main types flaggy quartzose granulites and garnetiferous 
muscovite-biotite schists with intermediate varieties the whole 
evidently representing an altered sedimentary series. Bands of 
garnetiferous hornblende-schist are intercalated in these granulitic 
schists, which are, without doubt, deformed intrusive sheets of igneous 
material. The lithological characters of the strata, the order of succes- 
sion, and the peculiar system of folding are magnificently displayed 
on Ben Hope (3040 feet), where the divisional planes generally dip to 
the east-south-east at angles varying from 12 to 30. But in addition 
to these members of the Moine series, which are now generally regarded 
as altered sediments, there are belts of massive, hornblendic, and 
micaceous gneisses resembling the Lewisian types in the north-west of 
Sutherland. The precise relationship of these two divisions of the 
crystalline schists has not been definitely ascertained in this district, 
but it is sufficiently clear that they have been affected by a common 
system of folding, and in certain localities by common planes of 
schistosity. From the north coast, these massive basic and acid gneisses 
of Archaean type stretch southwards along the west side of the Borgie 
valley to Loch Creagach, near Loch Laoghal, and another belt of 
somewhat similar materials has been traced from the village of Tongue 
northwards by Ribigill to Loch an Dithreibh. 

After the eastern schists had assumed their present crystalline 
characters, they were pierced by intrusive masses of granite, which 
form a picturesque group of peaks on Beinn Laoghal, south of Tongue. 
The mapping of that area leads to the conclusion that the granite there 
forms a great sill-like intrusion, which, on the north-east side of the 
loch of that name, branches off into minor sheets, or apophyses. 

On the east side of the Kyle of Tongue there are various small 
outliers of Old Red Sandstone, largely composed of conglomerate, as, 
for instance on Cnoc Creagach, on Beinn Bhreac, and on Cnoc an 
Fhreiceadain, which rest unconformably on the crystalline schists. 
They contain fragments of the various component members of the 
underlying platform, together with blocks of Cambrian quartzite and 
limestone. 

Loch Hope. The lower portion of this lake, measuring about 2 miles 
in length, is floored by thrust masses of Lewisian gneiss and deformed 
schistose rocks affected by the Post-Cambrian movements, while the 



THE FRESH-WATER LOCHS OF SCOTLAND. 329 

lip of the basin, above the point where the loch discharges into the 
river Hope, is composed of Lewisian gneiss on the east side and 
Cambrian quartzites on the west. No rock is visible at the mouth of 
the lake, nor in the course of the stream that connects it with the sea. 
On either side of the river Hope there are alluvial terraces, eroded 
partly out of solid rock and partly out of raised beach deposits. There 
are the remains of the 100-feet beach by the river Hope, and of the 
50-feet beach at the head of the lake ; hence it is evident that during 
their deposition the sea must have extended far up the valley. 

The lower portion of the lake lies along a line of fault trending 
nearly north and south, which is evidently continued northwards along 
the channel of the river Hope, though concealed by the alluvial deposits. 
On either side of this line there has been a lateral shift of the outcrops 
of the various groups of rock, indicating a downthrow to the east. This 
dislocation has been proved to traverse that portion of land that juts 
into the loch on the west side about a mile south of Poll Ath-roinn, 
where the quartzose flagstones of the Moiiie series have been thrown 
down against a narrow belt of deformed Lewisian gneiss. Though the 
whole of Strath Mor (the valley above Loch Hope) has not been mapped 
by the Geological Survey, it is not improbable, judging from the straight 
feature, that the fault may be prolonged southwards, and may have 
been a prominent factor in determining the original course of the valley. 

Though no rock is seen at the outlet of the lake, it is not improbable 
that it may be a rock basin. Its widest and deepest part lies within 
the area occupied by the eastern or Moine schists (Geological Survey), 
just above the belts of displaced and deformed Lewisian gneisses and 
the crushed schistose rocks in association with them. Bounded by the 
75-feet contour-line, this upper basin extends for 1| miles above the 
narrows, with an average breadth of one-third of a mile. A second 
basin, with a maximum depth of 104 feet, occurs further down, opposite 
Poll Ath-roinn, which is carved out of a belt of Lewisian gneiss and 
the mylonized rocks above the Moine thrust-plane. 

As the surface of the water in Loch Hope is only 12 feet above sea- 
level, the greater part of the lake is below the level of the sea. 

The striae and the distribution of the drift indicate that during the 
early and later glaciatioiis the ice moved from the south towards the 
north, so that the trend of the lake coincides generally with the 
direction of ice-movement. 

Loch Laoghal, Loch Creagach, and Loch Slaim. The rocks under- 
lying this chain of lochs consist of hornblendic gneisses exposed on 
either side of Loch Slaim, of granulitic micaceous gneisses of the Moine 
series, and the granite of Beinn Laoghal and Beinn's Tomaine. Along 
the northern margin of this granite mass the strike of the schists is 
nearly east and west, the general dip of the foliation planes being 
towards the south at angles varying from 20 to 70. These rocks are 



330 BATHYMETRICAL SURVEY OF 

visible at certain localities on either side of Loch Creagach, and on the 
ridges east and west of the lower end of Loch Laoghal, where they pass 
underneath the sill-like mass of granite and its apophyses. For a 
distance of upwards of 2 miles from the foot of Loch Laoghal granite 
occurs on both banks of the lake, but in the southern portion the 
granite extends continuously along the west side, while the crystalline 
schists occur at intervals on the east side. 

Though these three lakes are now separated from each other, they 
may be regarded as one sheet of water, as they are nearly at the same 
level. The strip between Loch Slaim and Loch Creagach consists partly 
of moraine matter and partly of the same material arranged in the 
form of terraces rising to about the 400-feet contour-line. The barrier 
between Lochs Creagach and Laoghal is composed partly of terraced 
morainic matter, partly of alluvium brought down by the stream 
draining the north slope of Beinn's Tomaine, and partly of gravelly 
material driven along the spit by the prevalent west wind. 

An alluvial terrace, about the 400-feet level, connects the three 
lakes, thereby indicating that they must have been at one time con- 
tinuous. This feature does not occur in the upper part of Loch Laoghal, 
where the unmodified moraines extend downwards to the present shore 
of the loch. It is not improbable, therefore, that the upper portion may 
have been occupied by a glacier while the barrier of moraines beyond 
Loch Slaim was being lowered. 

But though these lakes are ponded back by moraines at the surface, 
it would appear that the lower portions of Loch Creagach and Loch 
Laoghal may be rock basins, for at a distance of about 1J miles below 
Loch Slaim the river Borgie flows over a rocky floor of hornblendic 
gneiss at a height of 304 feet, while the surface level of the two upper 
lochs is 369 feet. The difference between these elevations is 65 feet. 
On referring to the chart of the soundings, it will be seen that the 
greatest depth of Loch Creagach is 84 feet, of the lower basin of Loch 
Laoghal 217 feet, and of the upper basin 137 feet. If, then, we assume 
that the rocky barrier 1J miles below Loch Slaim, near Dailaneas, 
crosses the valley at the same level (304 feet) underneath the drift, 
then it follows that the depth of water below the rocky barrier is in 
the case of Loch Creagach 19 feet, of the lower basin of Loch Laoghal 
152 feet, and of the upper basin 72 feet. The deepest part of Loch 
Laoghal occurs where the valley is most constricted, and where the 
hills on either side are loftiest. 

Although no glacial markings have been found in the immediate 
neighbourhood of the lochs, the striae in the surrounding district show 
that the ice-movement during the period of maximum glaciation was 
slightly west of north. The dispersal of the boulders and the disposition 
of the moraines indicate that during the later glaciation a confluent 
glacier moved northwards from the interior, one branch skirting the 



THE FRESH-WATER LOCHS OF SCOTLAND. 331 

western slope of Beinu Laoghal, a second passing through the hollow 
occupied by the loch of that name, and a third round the eastern slope 
of Benin's Tomaine. The stages in the gradual retreat of the mass of 
ice that moved down the valley of Loch Laoghal are clearly marked by 
a succession of moraine terraces, which enclose the small lochans shown 
on the chart to the east of Loch Creagach and Loch Slaim. 

Loch an Dithreibh is a rock basin lying in hornblendic and micaceous 
gneisses, whose strike is nearly north and south and nearly parallel to 
the direction of the lake. They are admirably exposed on the great crag 
on the east side of the loch. The solid rock is not exposed at the lip 
of the basin, but at a point in the stream about a quarter of a mile below 
the outlet at a height of 261 feet, the surface of the loch being 267 feet 
above sea-level, and the deepest part of the basin being 157 feet. 

Loch Syre, like many of the lochans east of Loch Laoghal, is sur- 
rounded with morainic deposits. 



NOTES ON THE BIOLOGY OF THE LOCHS OF NORTH SUTHERLANDSHIRE. 
By JAMES MURRAY. 

Tow-nettings were taken in seven of the lochs. These include three 
deep lochs (Hope, an Dithreibh, and Laoghal), two very shallow lochs 
(Chaluim and na Meide), while Loch Naver is intermediate. The 
biological phenomena are in accordance with those differences, the 
plankton of the deep lakes being relatively poor, and similar to that of 
great lakes in general, the shallow lakes having a large admixture of 
littoral forms. 

All the lochs were rich in algae, especially Desmids, including many 
of those conspicuous species of western type, alluded to by Messrs. 
West, which are so characteristic of the extreme north-western fringe 
of Europe. The northern species of Diaptomus D. laciniatus, D. 
laticeps, and D. Wierzejskii which are so widely distributed in the 
north of Scotland, Orkney, Shetland, and the western isles, and which 
are common in many lochs immediately adjacent, both to the east and 
south, are absent from most of the lochs of this district. D. laticeps 
is in Lochs na Meide and Naver, D. laciniatus in Loch na Meide only. 
D. gracilis is in six of the lochs, and in five it is the only species. 

In the short lists of organisms following the name of each loch, 
species of general distribution are omitted, only those being included 
which are interesting on account of their distribution or rarity. 

Loch Hope. Leptodora, Daphnia hyalina (head rounded), Dia- 
phanotsuma, Fluscularia pelayica, Triarthra lonyiseta, Clathrulina 



332 BATHYMETRICAL SURVEY OF 

elegans, Micr aster ias furcata, Staurastrum furcigerum, Xanthidium 
subhastiferum. 

Loch an Dithreibh. Bosmina obtusirostris, var. longispina, Flos- 
cularia pelagica, Staurastrum ophiura, cysts of Ceratium. Animal 
life (both as to individuals and species) was very scarce, while the 
smaller algae were conspicuous. 

Loch na Meide. Diaptomus laticeps, D. laciniatus, Cyclops gigas, 
Daphnia (galeate), Ilyocryptus acutifrons, Gastropus stylifer ( = Notops 
pygmceus), Staurastrum ophiura, S. arctiscon, 8. pseudopelagicum, 
Micr aster ias apiculata, var. fimbriata. This loch was remarkable for 
the abundance of both animal and plant life ; about eighty species of 
organisms were found in the first cursory examination. The true 
plankton was not, however, particularly rich, there being a very large 
admixture of littoral species. Ilyocryptus acutifrons was first observed 
in Scotland in this loch, though it was afterwards found that it had been 
collected in Loch Shin at an earlier date. 

Loch Naver. Diaptomus laticeps, Bosmina obtusirostris (small, with 
long spine), Floscularia pelagica, Gastropus stylifer, Staurastrum 
ophiura, S. arctiscon, S. grande, Micrasterias conferta, M. furcata 
(typical, also a variety having the whole surface covered with hemis- 
pherical papillae of unequal sizes). 

Loch Chaluim. Daphnia (two forms, first with small rounded head, 
second with very large broad, depressed head, many males), Syncluzta 
pectinata, Gastropus stylifer, Polychcetus collinsi, Staurastrum ophiura, 
S. arctiscon, S. furcigerum. 

Loch Laoghal. Bosmina obtusirostris, var. longispina, Floscularia 
pelagica, Triarthra longiseta, Clathrulina elegans, Staurastrum pseudo- 
pelagicum, S. jaculiferum. 

Loch Creagach is connected with Loch Laoghal by a wide channel, 
and stands at the same level. The biology calls for no separate mention. 

NOTE ON Clathrulina elegans, Cienk. Skeletons of this animal were 
abundant in the deep lochs Hope and Laoghal. In an earlier paper* 
an attempt was made to account for the presence of these empty shells 
in so many of the Scottish lochs, and as a general rule only in large 
ones, on the supposition that they were derived from the shallow waters 
in which C '. elegans is known to live, attached to water-plants by a 
slender stalk. Up till quite recently only empty cases had been found, 
or at most an occasional shell containing an encysted mass of protoplasm, 
and on these facts was based the suggestion put forward as to their 
origin. A fresh aspect is put upon the inquiry by the recent observation 
that in Loch Lochy, where the animal was abundant in August, 1905, 
when the loch was visited in company of Prof. Bachmann, most of the 
shells contained living animals, which extended their pseudopodia and 

* See p. 291. 



THE FRESH- WATER LOCHS OF SCOTLAND. 333 

seemed quite at home. There was in no instance any trace of a stalk. 
These facts led to the supposition that perhaps the lacustrine form may 
be a permanent pelagic race, or even a distinct species. Or it may be 
that the animal is attached when young, and becomes free when adult. 
There are difficulties in the way of accepting either hypothesis. If it be 
a true plankton form, we have to explain the absence of living animals 
from so many of the Scottish lochs in which the skeletons occur, and 
some of which have been examined at all seasons of the year. If it be 
a littoral form, and only casual in the plankton, it is still unexplained 
why the skeletons are, as a rule, only in large lakes. 



334 BATHYMETRICAL SURVEY OF 



LOCHS OF THE BEAULY BASIN. 

THE Beauly basin is an important and extensive one, extending across 
almost the entire width of Scotland, from Beauly firth on the east 
coast to within about 4 miles from the shores of Loch Duich, and 
about 6 miles from the shores of Loch Carron, on the west coast. The 
basin is situated in a very mountainous district, many of the peaks in 
the central and western part of the basin exceeding 3000 feet, and 
some of them approaching 4000 feet, in height, while on proceeding 
eastward towards the outlet of the basin the land becomes gradually 
less elevated. On the southern boundary of the basin are Tigh Mor 
(3222 feet), Sgurr nan Conbhairean (3634 feet), Garbh Leac (3673 feet), 
Sgurr nan Ceathramhan (3614 feet), Ciste Dhubh (3218 feet), Cam 
Fuaraloch (3241 feet), and Sgurr a' Bhealaich Dheirg (3378 feet) ; on 
the western boundary Beinn Fhada (Ben Attow, 3383 feet), Sgiirr nan 
Ceathreamhnan (3771 feet), Lurg Mhor (3234 feet), and Sgiirr Choin- 
nich (3260 feet), on the northern boundary Sgiirr a' Chaoruinn (3452 
feet), Bidean an Eoin Deirg (3430 feet), Maoile Lunndaidh (3294 feet), 
Sgiirr Fhuar-Thuill (3439 feet), Sgorr a' Choir-Ghlais (3552 feet), and 
Sgurr Ruadh (3254 feet) ; while in the central part of the basin are 
Craig Dhubh (3102 feet), Sgiirr na Lapaich (3773 feet), An Riabhachan 
(3696 feet), Beinn Fhionnlaidh (3294 feet), Mam Sodhail (Mam Soul, 
3862 feet), Cam Eige (3877 feet), Tom a' Choinich (3646 feet), a 
second peak named Sgurr na Lapaich (3401 feet), and Tuill Creagach 
(3452 feet). Besides these heights there are many others which do 
not attain the 3000-feet level. In the valleys between these chains of 
mountains lie the lochs which were sounded by the Lake Survey staff. 
In the most northerly valley, Glen Strath Farrar, there is the con- 
nected series consisting of Lochs Calavie, an Tachdaidh, an Gead, 
Monar, a' Mhuilinn, and Bunacharan ; in the central valley, Glen 
Cannich, the connected series of Lochs Lungard, Mullardoch, and 
Sealbhag ; and in the most southerly valley, Glen Affric, the connected 
series of Lochs Affric, an Laghair, and Beinn a' Mheadhoin ; with the 
isolated Loch na Beinne Baine as an outlier situated towards the head 
of Strath Glass. These valleys all trend in a more or less east-and- 
west direction, converging towards the north-east, where the river 



THE FRESH-WATER LOCHS OF SCOTLAND. 



335 



Beauly is formed by the junction of the river Farrar with the river 
Glass. The river Glass is formed by the junction of the Amhuinn 
Deabhaidh (bearing the outflow from Loch na Beinne Baine) with the 
river Affric, while the river Cannich is a tributary of the river Glass. 
The river-systems within the Beauly basin, and the relative positions 
of the different lochs, are shown on the accompanying index-map 
(Fig. 50). The area of the entire basin, as measured with the plani- 
meter on the 1-inch Ordnance Survey maps, is about 343 square miles, 
of which about 215 square miles (or 63 per cent.) drain into these 




J oartfiohme-w 



English Miles 

I * 3 4 S 



FIG. 50. INDEX MAP OF THE BEAULY BASIN. 



thirteen lochs, as will be seen from the summary table on p. 350. 
An inspection of the summary table shows, further, that all the 
lochs exceed half a mile in length, while eight of them exceed a 
mile in length; the two largest lochs (Mullardoch and Monar) exceed 
4 miles in length, and have each an area exceeding a square mile. 
Seven of the lochs exceed 100 feet in depth, and two of them exceed 
200 feet, the deepest one being Loch Monar, with a maximum depth 
of 260 feet; this loch is also the one containing the largest volume 
of water. The boundary-line between the counties of Inverness and 
Ross runs up the centre of Loch Monar for the greater part of its 
length, and it crosses Loch Mullardoch in its central portion, so that 



336 BATHYMETRICAL SURVEY OF 

these two lochs lie partly in Ross-shire and partly in Inverness-shire : 
four of the others (Lochs Lungard, Calavie, an Tachdaidh, and an Gead) 
are situated in Ross-shire, and the remaining seven in Inverness-shire. 
The scenery of the district around the lochs is very fine, and the trout 
fishing in most of the lochs very good ; some of them contain pike also. 

Loch Affric (see Plate LXX VIII.). Loch Affric (or Affaric) lies 
about 26 miles to the south-west of Beauly, which is the nearest railway 
station, and about 11 miles from Glen Affric Hotel at Cannich, the 
nearest house of entertainment. The loch trends in a west-south-west 
and east-north-easterly direction, and is nearly 3J miles in length. 
It is broadest towards the western end, where the maximum breadth 
is nearly half a mile, narrowing gradually, though irregularly, on 
proceeding towards the eastern end, the mean breadth of the entire 
loch being a quarter of a mile. The superficial area is about 526 acres, 
or over four-fifths of a square mile, and the area drained by the 
loch is nearly 47 square miles. The maximum depth of 221 feet was 
observed near the centre of the loch. The volume of water is estimated 
at 2146 millions of cubic feet, and the mean depth at nearly 94 feet. 
The loch was surveyed on October 6 and 7, 1903, when the elevation 
of the lake-surface above the sea was determined, by levelling from 
bench-mark, as being 747 '0 feet ; when levelled by the officers of the 
Ordnance Survey on July 3, 1867, the elevation was found to be 
744*1 feet above sea-level, or 3 feet lower than in 1903. 

Loch Affric is quite simple in conformation, the deeper water 
occupying a central position, from which the bottom slopes upward to 
the shores on all sides. The 50-feet contour coincides approximately 
with the outline of the loch, enclosing a basin nearly 2J miles in length, 
approaching comparatively close to the west end, but distant more than 
a quarter of a mile from the east end. Separated from this main 50- 
feet basin by shallower water is an isolated sounding of 54 feet, near 
the east end, where the main loch is joined by the little subsidiary basin 
called Loch Pollan Fearna, in which a maximum depth of 30 feet was 
observed. The 100-feet basin is 2J miles in length, and the 150-feet 
basin nearly H miles in length, approaching in each case nearer to the 
west end than to the east end. The 200-feet basin is about three-quarters 
of a mile in length, and is approximately equidistant from both ends of 
the loch, but the deepest sounding in 221 feet was taken towards the 
west end of the basin, and therefore nearer to the western end of the 
loch. A section along the centre of the loch from end to end is shown 
in the longitudinal section A-B on the map, and a section across the 
loch in the position of the deepest sounding is shown in cross-section 
C-D. This last section shows a very slight irregularity in the deepest 
part of the loch, where a sounding in 209 feet was taken between a 
sounding in 211 feet on the one hand, and the greatest depth of the 



THE FRESH- WATER LOCHS OF SCOTLAND. 337 

loch (221 feet) on the other. Another line of soundings, about three- 
quarters of a mile further east, shows a shoaling in deep water, where 
a depth of 122 feet was recorded between a depth of 130 feet on one 
side and 159 feet on the other. With these exceptions, the various 
lines of soundings show a regular bottom, with a steep offshore slope 
in some places along both the northern and southern shores. Thus, 
proceeding along the northern shore from the east end of the loch, the 
first line of soundings gave a depth of 40 feet at a distance of 20 feet 
from shore; the fourth line of soundings gave a similar depth at a 
similar distance ; the fifth line gave a depth of 28 feet at 10 feet from 
shore; the ninth line gave 47 feet at 30 feet; the next line gave 21 
feet at a distance of 20 feet ; the next line 84 feet at 60 feet distance ; 
the next 35 feet at 25 feet distance; and the next line 36 feet at 30 
feet distance. In like manner, proceeding along the southern shore from 
the east end, the sixth line of soundings gave a depth of 76 feet at a 
distance of 50 feet from shore; the next line gave 31 feet at 20 feet 
distance; the next line 47 feet at 15 feet distance; the next line 33 
feet at 20 feet distance ; and the next line 34 feet at 30 feet distance. 
All these figures indicate a slope exceeding 1 in 1, and in one case a 
slope exceeding 3 in 1. The following table gives the areas between 
the consecutive contour-lines at intervals of 50 feet, with the per- 
centages to the total area of the loch, the flat-bottomed character of 
the basin being indicated by the larger zone on the deeper side of the 
100-feet contour than on the shallower side: 

to 50 feet 195 acres 37 per cent. 

50,, 100 ,, 89 ,, 17 

100,, 150 125 24 

150,, 200 70 13 

Over 200 ,, 47 9 

526 , 100 ' 



Temperature Observations. A series of temperatures taken at 3 p.m. 
on October 6, 1903, in the deepest part of the loch, gave the following 
results : 

Surface 49-2 Fahr. 

10 feet 48-9 

25 48-6 

50 48-0 

100 47'0 

150 45-6 

200 44-8 

The extreme range shown by these observations is only 4-4 from 
surface to bottom, the fall of temperature being very gradual. 



338 BATHYMETRICAL SURVEY OF 

Loch an Laghair (see Plate LXXIX.). Loch an Laghair lies a 
little over a mile to the north-east of Loch Affric, and is practically 
continuous with Loch Beinn a' Mheadhoin, for normally the two lochs 
stand at the same level, although an easterly gale sets up a strong 
current through the narrows at Blar an Ath, in which a depth of 
5 feet was observed. The loch trends in a north-east and south-west 
direction, and is nearly two-thirds of a mile in length. The maximum 
width exceeds a quarter of a mile towards the western end, whence 
the loch narrows gradually towards the eastern end. The superficial 
area of the loch is about 83 acres, and the area draining directly into it 
nearly 6 square miles, but since it receives the overflow from Loch 
Affric its total drainage area is about 52J square miles, an area over 
400 times greater than that of the loch. The deepest sounding in 100 
feet was taken in the central part of the loch, but rather nearer to the 
north-east end. The volume of water is estimated at 135 million cubic 
feet, and the mean depth at 37J feet. The loch was surveyed on 
October 6, 1903; but the elevation of the lake-surface above the sea 
could not be determined by levelling, as there was no bench-mark near 
the loch. The level was estimated at about 703 feet above sea-level. 

Loch an Laghair forms a simple basin, the shallower contours 
coinciding approximately with the outline of the loch, but approaching 
closer to the northern shore in the eastern half of the loch, where the 
offshore slope is steepest. The western end is apparently being silted 
up. The 75-feet area is extremely small, for on each side of the 
deepest sounding in 100 feet, at a distance represented by twenty 
strokes of the oar, the depths were 66 and 64 feet respectively. A 
section across the loch at the position of the deepest sounding is shown 
in cross-section E-F on the map, and a section along both Loch an 
Laghair and Loch Beinn a' Mheadhoin is shown in the longitudinal 
section A-B. The area of the lake-floor in Loch an Laghair covered 
by less than 50 feet of water is about 63 acres, or 76 per cent, of the 
total area of the loch. The temperature of the surface water at 
3.30 p.m. on the date of the survey was 48'0 Fahr. 

Loch Beinn a' Mheadhoin (see Plate LXXIX.). Loch Beinn a' 
Mheadhoin (or Beinnavian, or Beneveian) trends generally in a north- 
east and south-westerly direction, and is over 2J miles in length. The 
loch is fairly uniform in width, the two end portions being somewhat 
narrower than the central portion, which has a maximum breadth of 
nearly half a mile, the mean breadth of the entire loch exceeding a 
quarter of a mile. The superficial area of the loch is about 504 acres, 
or over three-quarters of a square mile, and the area of land draining 
directly into it is about 15J square miles; but since it receives the 
superfluent waters from Lochs Affric and an Laghair, the total drainage 
area is about 68 square miles. The maximum depth of 167 feet was 



THE FRESH- WATER LOCHS OF SCOTLAND. 339 

observed in a central position, but nearer to the eastern than to the 
western end of the loch. The volume of water is estimated at 1435 
millions of cubic feet, and the mean depth at over 65 feet. The loch 
was surveyed on October 6, 1903, but the elevation of the lake-surface 
above the sea could not be determined by levelling. The water in the 
loch was very high on the date of the survey, the level then being 
estimated at about 703 feet above sea-level, but the normal level .is 
probably about 700 feet. 

Loch Beinn a' Mheadhoin is rather complex in conformation, in- 
cluding as it does three deep basins separated by shallower water. 
Near the western end of the loch is a small basin having a maximum 
depth of 95 feet, and near the eastern end is a larger basin having a 
maximum depth of 117 feet, while the largest and deepest basin occupies 
the central portion. The two ridges separating these three basins may 
be due to the deposition of material brought down by the streams 
entering the loch at these places along the northern shore, of which 
the westerly stream (Amhainn a' Ghlinne Fhiadhaich) is the more 
important; the maximum depth observed on the western ridge was 
69 feet, and on the eastern ridge 97 feet. The 25-feet and 50-feet 
contours are continuous from end to end of the loch, while the 75-feet 
contour is broken at the position of the western ridge, and the 100-feet 
contour is broken at the position of the eastern ridge. The eastern 
100-feet basin is nearly half a mile in length, and the main 100-feet 
basin nearly 1| miles in length; within the last-mentioned basin is a 
long, narrow 150-feet basin, based on soundings of 159, 167, and 154 
feet, with an isolated sounding in 156 feet a quarter of a mile farther 
west. It seems doubtful whether this isolated sounding may not be 
connected with the principal basin by deep water, and in that case the 
150-feet basin would be nearly a mile in length. The deepest sounding 
in 167 feet was recorded about a mile from the eastern end of the loch, 
and about H miles from the western end. The cross-section C-D, in 
this position, shows a steeper gradient off the northern than off the 
southern shore; but the soundings, as a whole, afford no evidence of 
any very steep slopes. The deeper part of the loch has quite a flat- 
bottomed character, as indicated by the figures in the following table, 
giving the areas between the consecutive contour-lines : 

to 25 feet 98 acres 19 '5 per cent. 

25,, 50 80 15-8 

50,, 75 96 19-0 

75 100 174 34-5 

Over 100 , 56 . 11-2 



504 , 100-0 



It will be observed that the largest zone is the one between 75 and 
100 feet, and that the area of the lake-floor covered by less than 50 feet 



340 BATHYMETRICAL SURVEY OF 

of water is about 178 acres, as compared with 270 acres covered by 
water between 50 and 100 feet in depth, or 35 per cent, as compared 
with 53 per cent. In most lakes the arrangement is the reverse of this, 
the areas between consecutive contour-lines drawn at equal intervals 
usually decreasing with increase of depth. The temperature of the 
surface water at the east end on commencing the survey was 50'0 
Fahr., while later in the afternoon, towards the opposite end the 
surface temperature was 49-5 ; but an easterly gale having sprung 
up, it was found impossible to take serial temperatures beneath the 
surface. 

Loch na Beinne Baine (see Plate LXXXIL). Loch na Beinne 
Baine lies in Guisachan forest, about 4 miles to the south-east of Loch 
Beinn a' Mheadhoin, and 8 or 9 miles to the west of Invermoriston on 
Loch Ness. It is irregular in outline, trends in a north-north-east and 
south-south-westerly direction, and is nearly a mile in length, with a 
maximum breadth of nearly half a mile. The superficial area is about 
154 acres, or a quarter of a square mile, and the area draining into it 
about 1J square miles. The maximum depth of 67 feet was observed 
about a quarter of a mile from the southern end of the loch, midway 
between an island of stones and the eastern shore. The volume of 
water is estimated at 190 million cubic feet, and the mean depth at 
28 J feet. The loch was surveyed on June 6, 1904, but the elevation of 
the lake-surface above the sea could not be determined ; the height of 
the water at the sluice was about 2 feet, and at one time the loch 
appears to have been considerably higher. 

Loch na Beinne Baine forms a simple basin ; the 25-feet contour 
coincides approximately with the outline of the loch, but is deflected at 
the position of the island of stones off the western shore towards the 
southern end, while the 50-feet basin, based on soundings of 67, 64, 54, 
and 52 feet, is contained in the southern half of the loch, and is about 
a quarter of a mile in length. The soundings indicate in one or two 
places slight undulations of the lake-floor, but as a rule the slope of 
the bottom is regular and gentle. The area covered by less than 25 feet 
of water is about 95 acres, or 62 per cent, of the total area. 

Temperature Observations. A series of temperatures taken in the 
deepest part of the loch gave the following results : 

Surface 60 '8 Fahr. 

10 feet 60'0 ,, 

20 50-5 

40 47'6 

60 ... 46'5 

These observations indicate an extreme range of temperature from 
surface to bottom amounting to 14-3, there being a fall of 9'5 between 



THE FRESH- WATER LOCHS OF SCOTLAND. 341 

10 and 20 feet, which is nearly equal to a fall in temperature of one 
degree per foot of depth. Reference has elsewhere been made to the 
large range and rapid fall of temperature observed in Lochs Monzie- 
vaird, Achilty, and Dubh,* and the temperatures here given from 
Loch na Beinne Baine afford another instance for comparison. 

Loch Lungard (see Plate LXXXIL). Loch Lungard (or Longart, 
or Glasletter) lies at the head of Glen Cannich, about 5 miles to the 
north of Loch Affric. It trends east and west, and is 1 J miles in length, 
with a maximum breadth towards the west end of one-third of a mile, 
whence the loch narrows gradually towards the east. The superficial 
area is about 216 acres, or one-third of a square mile, and the area 
draining into it is nearly 23 square miles. The maximum depth of 
129 feet was observed in a central position, but towards the east end. 
The volume of water is estimated at 599 million cubic feet, and the 
mean depth at nearly 64 feet. The loch was surveyed on October 7, 
1903, when the elevation of the lake-surface above the sea was found, 
by levelling from bench-mark, to be 761-3 feet, which is nearly identical 
with the level observed by the Ordnance Survey officers on October 14, 
1867, viz. 761-2 feet. When surveyed the water was about its normal 
level, and in floods might rise about 3 feet. 

Loch Lungard is extremely simple in conformation, the bottom 
sloping down on all sides towards the deepest part, not the slightest 
irregularity being indicated by the soundings, while the contour-lines 
coincide approximately with the outline of the loch. This is shown in 
both the longitudinal section A-B and the cross-section C-D on the 
map. The 50-feet basin is 1J miles, and the 100-feet basin rather under 
a mile, in length, and they are comparatively wide, so that the loch is 
of a flat-bottomed character, as is shown by the following table, giving 
the areas and percentages between the contour-lines : 

to 50 feet 87 acres 40 per cent. 

50,, 100 81 38 

Over 100 48 22 

216 100 

Temperature Observations. The following series of temperatures, 
taken at 2 p.m. on the date of the survey in the deepest part of the 
loch, indicates a range of only l-2 Fahr. throughout the body of 
water : 

Surface 49 '2 Fahr. 

25 feet 49-0 

50 48-8 

125 48-0 

* See p. 276. 



342 BATHYMETRICAL SURVF.Y OF 

Loch Mullardoch (see Plate LXXX.). Loch Mullardoch (or 
Mulardich, or Moyley) lies less than 2 miles to the east of Loch 
Lungard, and is practically continuous with Loch Sealbhag, there 
being a small expansion of the river between them called Loch Ath 
a' Bhan, which was not sounded. Loch Mullardoch trends generally 
in an east and westerly direction, and is somewhat irregular in outline, 
with a slight bend in the central portion. It exceeds 4 miles in length, 
and is pretty uniform in width, the maximum breadth being less than 
half a mile, and the mean breadth over a quarter of a mile. Its waters 
cover an area of about 756 acres, or considerably more than a square 
mile, and the area draining directly into it is about 27 J square miles ; 
but since it receives the outflow from Loch Lungard its total drainage 
area exceeds 50 square miles. The maximum depth of 197 feet was 
observed in the eastern portion of the loch, about a mile and a half 
from the east end. The volume of water is estimated at 2553 millions 
of cubic feet, and the mean depth at 77J feet. The loch was surveyed 
on October 7, 1903, but the elevation above the sea was not determined ; 
when levelled by the Ordnance Survey officers on November 29, 1866, 
the elevation of the lake-surface was found to be 704*9 feet above sea- 
level. On the date of the survey the water was about a foot above the 
normal level, and two days previously it had been 3 feet higher. 

Loch Mullardoch is divided into two deep basins by a shoaling of 
the water in its central portion, where there is a constriction and bend 
in the outline, the maximum depth in the western basin being 150 feet, 
and in the eastern basin 197 feet, the depth on the shoaling being 80 
feet. A section across the deepest part of the western basin is shown in 
cross-section C-D, and one across the deepest part of the eastern basin 
in cross-section E-F, on the map, and a section along the centre of the 
loch from end to end is shown in the longitudinal section A-B at the 
foot of the map. This last-mentioned section brings out the central 
shoaling referred to, which is apparently traceable to the influence of 
the streams entering on both sides of the loch at this place, and 
principally of the Allt Taige, at the mouth of which, on the northern 
shore, is a considerable delta. The 50-feet contour is continuous, and 
encloses a basin nearly 4 miles in length. The western 100-feet basin 
exceeds half a mile in length, separated by an interval of over half a 
mile from the eastern 100-feet basin, which is one and a half miles in 
length, and includes a 1 50-feet basin over a mile in length. All the 
cross-lines of soundings show a regular bottom, the water deepening 
gradually from the shore towards the centre, with a steep offshore slope 
in some places, as, for instance, along the southern shore off Creag 
Dubh, where a sounding in 24 feet was taken about 20 feet from shore, 
and off Creag a' Bhaca, at the deepest part of the loch, where a sounding 
in 94 feet was taken about 100 feet from shore. The following table 
gives the approximate areas between the consecutive contour-lines at 



THE FRESH- WATER LOCHS OF SCOTLAND. 343 

intervals of 50 feet, and the percentages to the total area of the loch, 
and indicates the flat-bottomed character of the basin, the comparatively 
large area of the lake-floor covered by more than 150 feet of water 
being noteworthy : 

to 50 feet 298 acres 39 per cent. 

50,, 100 228 30 

100,, 150 ,, 121 16 

Over 150 , 109 . 15 



756 100 

Temperature Observations. The following series of temperatures, 
taken at 4.30 p.m. on the date of the survey in the western basin, 
shows that the water was nearly uniform in temperature, the extreme 
range from surface to bottom being only 1 Fahr., the readings down 
to a depth of 50 feet being identical: 

Surface 50 '0 Fahr. 

lOfeet 50-0 ,, 

25 50-0 

50 50'0 

100 49-5 

150 : 49-0 

Loch Sealbhag (see Plate LXXX.). Loch Sealbhag lies to the east 
of, and is, as already stated, practically a continuation of Loch Mullar- 
doch. It trends in a north-east and south-westerly direction, and is 
two-thirds of a mile in length, with a maximum breadth towards the 
west end of nearly a quarter of a mile, whence it narrows gradually 
towards the north-east. Its waters cover an area of about 68 acres, and 
it drains directly an area of 3J square miles, but since it receives the 
outflow from Lochs Lungard and Mullardoch, its total drainage area 
is nearly 54 square miles an area nearly 500 times greater than that 
of the loch. The maximum depth of 56 feet was observed in the 
widest part of the loch towards the western end, and comparatively 
near the southern shore. The volume of water is estimated at 61 
million cubic feet, and the mean depth at over 20| feet. The loch 
was surveyed on October 5, 1903, but the elevation above the sea could 
not be determined. 

The wide western portion of Loch Sealbhag includes a deep basin 
exceeding 30 feet in depth, which approaches comparatively close 
to the western end, and is over a quarter of a mile in length. To 
the north-east of this basin the bottom rises, and falls again on 
approaching the outfall to a depth of 31 feet, the depth on the rise 
being 16 feet. The area of the lake-floor covered by less than 20 feet 
of water is about 39 acres, or 57 per cent, of the total area. The 
temperature of the surface water on the date of the survey was 
50-5 Fahr. 



344 BATHYMETRICAL SURVEY OF 

Loch Calavie (see Plate LXXXII.). Loch Calavie (or Calvie) lies 
about 6 miles to the north-west of Loch Lungard, and only 7 miles from 
the head of Loch Carron on the west coast of Scotland, at a high 
elevation among the mountains, the lower slopes of which are covered 
with peat. The loch trends in a north-west and south-easterly direction, 
and is considerably over a mile in length, with a maximum width 
towards the western end exceeding one-third of a mile, whence the 
breadth gradually decreases on approaching the eastern end. The 
superficial area is about 167 acres, or a quarter of a square mile, and 
the area draining into it nearly 2| square miles. The maximum depth 
of 84 feet was observed in a central position, but rather nearer the 
western than the eastern end. The volume of water is estimated 
at 276 million cubic feet, and the mean depth at 38 feet. The loch 
was surveyed on October 19, 1904, when the elevation was found by 
levelling from bench-mark to be 1128-35 feet above the sea a little 
lower than the elevation as determined by the Ordnance Survey officers 
on August 14, 1866, viz. 1128-5 feet above sea-level. 

Loch Calavie is perfectly simple in conformation, the contour-lines 
coinciding approximately with the shore-line, though in each case they 
approach nearer to the western than to the eastern end of the loch, so 
that the average slope is steeper towards the head of the loch. This 
is shown in the longitudinal section A-B on the map. The 25 -feet 
basin is nearly a mile, and the 50-feet basin three-quarters of a mile, 
in length. The soundings give no indication of any steep offshore 
slopes, and the average slope between the 25-feet and 50-feet contours 
is less steep than in shallower water, as indicated in the following 
table by the larger area beyond the 25-feet line: 

to 25 feet 55 acres 33 per cent. 

25 50 62 37 

50,, 75 39 ,, 24 

Over 75 11 ,, 6 

167 , 100 



Temperature Observations. The following series of temperatures 
taken in the deepest part of the loch shows that on the date of the 
survey the whole body of water was practically uniform in temperature, 
the extreme range being less than 1 Fahr. : 

Surface 47'OFahr.. 

40 feet 46-3 

75 46-2 ,, 

Loch an Tachdaidh (see Plate LXXXII.). Loch an Tachdaidh 
lies about 2 miles to the east of Loch Calavie, and is almost continuous 
with Loch an Gead, the stream between them being a very short one, 






THE FRESH- WATER LOCHS OF SCOTLAND. 345 

and the difference in level only 1^ feet. The term Gedd Lochs is 
applied to the connected series, consisting of Loch an Gead, Loch an 
Tachdaidh, and the neighbouring little Loch an Gobhlach, which was 
not sounded. Loch an Tachdaidh is irregular in outline, trends in a 
north-east and south-westerly direction, and is nearly two-thirds of a 
mile in length, with a maximum breadth exceeding one-third of a mile. 
Its waters cover an area of about 92 acres, and it drains directly an 
area exceeding 4 square miles, but since it receives the overflow from 
Loch Calavie, its total drainage area is over 6J square miles. The 
maximum depth of 62 feet was observed in the centre of the north- 
eastern portion of the loch, near a heap of stones showing above the 
surface of the water. The volume of water is estimated at 72 million 
cubic feet, and the mean depth at 18 feet. The loch was surveyed on 
October 21, 1904; the elevation could not be determined by levelling, 
but was estimated at about 831 '5 feet above the sea. 

Loch an Tachdaidh is irregular in conformation as well as in out- 
line, and, besides the island of stones already mentioned, includes four 
small unnamed islands, the largest of which occupies a central position ; 
the south-western portion is shallow and filled with weeds. The 
contour-lines are sinuous in character, the deepest part lying between 
the largest island and the heap of stones, where three soundings ex- 
ceeding 50 feet in depth were taken. To the south of the largest 
island, and towards the eastern shore, a sounding in 25 feet was 
recorded, surrounded by shallower water. The area of the lake-floor 
covered by less than 25 feet of water is about 74 acres, or 8.1 per cent, 
of the total area. 

Temperature Observations. The following series of temperatures 
taken in the position of the deepest sounding shows a range of only 
1'2 Fahr. throughout the body of water, the deeper layers being 
uniform in temperature : 

Surface 46 -2 Fahr. 

30 feet 45-0 

60 45-0 

An Gead Loch (see Plate LXXXII.). An Gead Loch lies to the 
north-east of Loch an Tachdaidh, and trends in a similar direction, but 
is more regular in outline and more uniform in width. An Gead Loch 
is nearly 1J miles in length, with a maximum width towards the south- 
west end of a quarter of a mile. The superficial area is about 110 acres, 
and the area draining directly into it is about 2J square miles, but 
since it receives the outflow from Lochs Calavie and an Tachdaidh, 
the total drainage area exceeds 9 square miles. The maximum depth of 
30 feet was observed towards the north-eastern end of the loch. The 
volume of water is estimated at 54 million cubic feet, and the mean 
depth at 11 J feet. The loch was surveyed on October 21, 1904, and the 



346 BATHYMETRICAL SURVEY OF 

elevation was estimated at about 830 feet above sea-level. The bottom 
of an Gead Loch is irregular and stony, so much so that in the deeper 
part no mud could be got, while the shallow western portion is covered 
with sand. Though irregular, the basin has a flat-bottomed character, 
for the majority of the soundings were taken in depths exceeding 10 
feet, and only three soundings in depths exceeding 20 feet. The area of 
the lake-floor covered by more than 10 feet of water is about 62 acres, 
or 56 per cent, of the total area. The temperature of the water was 
nearly uniform on the date of the survey, a reading at the surface 
giving 46-7 Fahr., and a reading at 25 feet 46-0. 

Loch Monar (see Plate LXXXI.). Loch Monar lies at the head 
of Glen Strath Farrar, little more than a mile to the north-east of 
an Gead Loch, and is one of the most important lochs in the Beauly 
basin. In length and in superficial area it is slightly inferior to Loch 
Mullardoch, but it is the deepest of the series, and contains the largest 
volume of water. The general trend of Loch Monar is east and west, 
but with a slight sinuosity in the outline, the length exceeding 4 miles. 
The width varies considerably, the maximum breadth of nearly half a 
mile occurring near the west end, the mean breadth of the entire loch 
exceeding a quarter of a mile. The waters of the loch cover an area 
of about 750 acres, or over one square mile, and the area draining 
directly into it is about 41 square miles, but since it receives the 
overflow from Lochs Calavie, an Tachdaidh, and an Gead, the total 
drainage area is about 50 square miles. The maximum depth of 260 
feet was observed much nearer the eastern than the western end. 
The volume of water is estimated at 3213 millions of cubic feet, and 
the mean depth at 98J feet. The loch was surveyed on October 10, 
1903, when the elevation of the lake-surface above the sea was found 
to be 663-9 feet ; when levelled by the officers of the Ordnance Survey 
on June 20, 1866, the elevation was 662-8 feet above sea-level. At the 
time of the survey the water was about its normal level, and might 
rise to the extent of several feet. 

Loch Monar is quite simple in conformation, all the contour-lines 
enclosing continuous areas, and the cross-lines of soundings indicating 
a regularly sloping bottom from the shores out towards the centre of 
the loch. The longitudinal section, A-B on the map, along the centre 
of the loch from end to end shows slight undulations of the lake-floor, 
the shallowings coinciding with constrictions in the outline. The 
contour-lines all approach nearer to the eastern than to the western 
end of the loch, showing a steeper slope in an easterly direction from 
the deepest sounding, which was taken less than a mile from the east 
end, or one-fourth of the distance from one end to the other. The off- 
shore slope is in places very steep, especially along the southern shore 
at the deepest part of the loch, where near the centre of the loch a 



THE FRESH-WATER LOCHS OF SCOTLAND. 347 

sounding in 104 feet was taken about 120 feet from shore; a little 
farther east another sounding in 50 feet was taken about 50 feet from 
shore; still farther east a sounding in 148 feet was taken about 120 
feet from shore ; and still farther east a sounding in 87 feet about 
60 feet from shore. The last-mentioned sounding, which gives a slope 
of 29 in 20, was taken on the cross-line immediately to the east 
of the deepest sounding, and the steepest gradient observed off the 
northern shore was at the opposite end of the same line, where a 
sounding in 54 feet was taken at about 60 feet from shore. The cross- 
section C-D on the map is taken at the position of the deepest sounding, 
and shows a gentle offshore slope, succeeded by a steeper slope on 
proceeding into deep water, the deeper part of the loch being of a 
flat-bottomed character. The area enclosed by the 50-feet contour is 
nearly 3 J miles in length, being distant from the west end nearly three- 
quarters of a mile, and extending into the narrow part at the east end 
off Creag Ghrada ; in the expansion of the out-flowing river, opposite 
Creag Dubh, a depth of 64 feet was observed. The 100-feet basin 
is 3 miles, the 150-feet basin 2J miles, and the 200-feet basin over one 
mile, in length. The approximate areas between the consecutive 
contour-lines drawn in at equal intervals, and the percentages to the 
total area of the loch, are given in the following table, from which 
it will be noticed that the area of the zone between 150 and 200 feet is 
larger than that of the two preceding shallower zones : 

Oto 50 fee